Skip to content

Journeys of Life StoryMD Health Communities

Men's Reproductive Health

Table of Contents

Men's Reproductive Health

Men's Reproductive Health

Image by TheVisualMD

How to Protect Reproductive Health?

Condom

Image by Sasin Tipchai/Pixabay

How Can Men Protect Their Reproductive Health and the Health of Their Partners?

It is important for men to protect their reproductive health and that of their partners by:

Using contraception carefully, consistently, and correctly
Minimizing the risk of sexually transmitted diseases
Addressing factors that may reduce fertility and seeking treatment when required

Men should consult with their healthcare provider to discuss which contraceptive method is best for the couple, based on overall health, age, frequency of sexual activity, number of partners, desire to have children in the future, and family history of certain diseases. Contraceptive methods work best when they are used correctly and consistently. Using contraception incorrectly or inconsistently increases the risk of pregnancy and in some cases also increases the risk of STDs.

It is important to discuss the risk factors for STDs with a healthcare provider and ask about getting tested. It is possible to have an STD and not know it, because many STDs do not cause symptoms. Men with STDs need to ask a healthcare provider about treatment to address symptoms, reduce the progression of the STDs, and decrease or eliminate the risk of transmitting an STD to your partner.

If you and your partner are interested in having children, but have difficulty conceiving, it is important for both the male and the female partner to consult with a healthcare provider to assess fertility. Over one-third of infertility cases are caused by male reproductive issues, alone or in combination with female reproductive issues. However, treatments are available to address many of the causes of male infertility.

Source: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Additional Materials (5)

Colorful Condoms

Bruno/Germany/Pixabay

Sensitive content

This media may include sensitive content

Illustration demonstrating a male condom.

BruceBlaus

Sensitive content

This media may include sensitive content

Illustration depicting a method of catheterization done by rolling a condom over the penis.

BruceBlaus

Sensitive content

This media may include sensitive content

Illustration demonstrating how to apply a condom.

BruceBlaus

Contraception: condoms

kerryank

Contraception

Sensitive content

This media may include sensitive content

Condom for safe sex

Image by TheVisualMD

How Effective Is Male Contraception?

Not all contraceptive methods are appropriate for all situations, and individuals should consult their healthcare providers to determine which method of birth control is best for them. For men, methods of contraception include male condoms and sterilization (vasectomy).

Male condoms. This condom is a thin sheath that covers the penis to collect sperm and prevent it from entering the woman's body. Male condoms are generally made of latex or polyurethane, but a natural alternative is lambskin (made from the intestinal membrane of lambs). Latex or polyurethane condoms reduce the risk of spreading sexually transmitted diseases (STDs). Lambskin condoms do not prevent STDs. Male condoms are disposable after a single use.
Vasectomy is a surgical procedure that cuts, closes, or blocks the vas deferens. This procedure blocks the path between the testes and the urethra.³ The sperm cannot leave the testes and cannot reach the egg. It can take as long as 3 months for the procedure to be fully effective. A backup method of contraception is used until tests confirm that there is no sperm in the semen. Although vasectomy can sometimes be reversed, it is not always possible. Vasectomy, like other sterilization procedures, is considered a permanent form of birth control.

Different methods of contraception have different rates of effectiveness in preventing pregnancy.

Contraception is most effective when used correctly and consistently. The failure rate increases if a method of contraception is used incorrectly.

According to the U.S. Department of Health and Human Services, male condoms have a failure rate of 11% to 16% (that is, from 11 to 16 women would be expected to get pregnant within one year if 100 women and their partners relied solely on male condoms for birth control). Male sterilization procedures have a failure rate of less than 1% if a backup method is used for the first several months after the procedure.

Source: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

STDs

Medical Illustration still showing Gonorrhea.

Image by Scientific Animations, Inc.

How Can Men Reduce the Risk of Getting a Sexually Transmitted Disease (STD)?

Men can take the following measures to avoid STDs:

Know your partner's STD and health history
Talk to your healthcare provider about your risk, and get tested for STDs
Practice safe sex (such using latex condoms correctly and consistently)
Get vaccinated against hepatitis A virus, hepatitis B virus, and human papilloma virus

According to the U.S. Department of Health and Human Services, the male latex condom is the best method for protecting against STDs, including HIV/AIDS. Polyurethane condoms are an effective alternative if either partner has a latex allergy. Natural/lambskin condoms do not prevent the spread of STDs because of the presence of tiny pores (holes) that may allow viruses such as HIV, hepatitis B, and herpes to spread.

It is important to know that male condoms cannot completely protect you and your partner from contracting an STD. For example, the most common STD is the human papilloma virus, or HPV. No method of contraception can fully prevent the transmission of HPV, because it can infect areas not covered by a condom. However, using a condom with every sex act can lower the risk of transmission.

It is important to discuss the risk factors for STDs with your healthcare provider and ask about getting tested. It is possible to have an STD and not know it, because many STDs do not cause symptoms.

See your healthcare provider for treatment as soon as possible after receiving a diagnosis of an STD. Notify all recent sex partners and advise them to see their healthcare providers and be treated. All sexual partners should be treated at the same time, to prevent re-infection. All partners should avoid sex until treatment is complete and your healthcare provider advises that it is safe to resume.

Many STDs have significant health consequences. Infections from STDs can cause infertility in both men and women. Some STDs can increase the risk of some forms of cancer. STDs can be passed on to the fetus during pregnancy or delivery. A person with an STD other than HIV is two to five times more likely to contract the HIV virus than a person without an STD. If a person is already HIV positive, having another STD increases the chances that they will pass the HIV virus on to their sexual partner.

Source: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Additional Materials (3)

Illustration of drug-resistant Neisseria gonorrhoeae bacteria

CDC/ Antibiotic Resistance Coordination and Strategy Unit; Photo credit: Medical Illustrator: Alissa Eckert

Sexual Health

TheVisualMD

Ways HIV is Not Transmitted

Ways HIV is Not Transmitted

Infertility

Sensitive content

This media may include sensitive content

Lifestyle and Age Can Effect Fertility

Image by TheVisualMD

Evaluating Male Fertility

Health care providers evaluate men and women differently to diagnose infertility.

The evaluation of a man's fertility includes looking for signs of hormone deficiency, such as increased body fat, decreased muscle mass, and decreased facial and body hair. The evaluation also includes questions about the man's health history, including:

Past injury to the testicles or penis
Recent high fevers
Childhood diseases, such as mumps
Low sexual desire (libido)

A physical examination of the testes and penis allows for identification of problems, such as:

Infection, signaled by discharge or prostate swelling
Hernia
Malformed tubes that transport sperm
Hormone deficiency as indicated by small testes or lack of facial and body hair
Presence of a mass in the testicles
Varicocele (abnormal veins in the scrotum)

A health care provider may also ask a man to provide a sample of semen to assess the health and quality of his sperm. To give a semen sample, the man is requested to refrain from ejaculation for around 48 hours before the test. He then provides a sample by masturbating into a cup or by having intercourse using a special condom (without contraceptive) that collects semen without affecting the sperm. A man may need to provide a semen sample on more than one occasion, because sperm production can vary over time depending on the man's current health status, activities, and stress level.

Other tests may include:

Measurement of hormones in the blood, including testosterone and follicle-stimulating hormone, thyroid hormones, and prolactin
Biopsy of the testicle. A health care provider uses a needle to extract sperm from the testicle.
Genetic testing. In cases where no or very few sperm are found in the semen, a health care provider may do genetic testing before starting fertility treatments. Testing can identify chromosome abnormalities that may cause the lack of sperm or lead to developmental problems among offspring.

Source: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Additional Materials (10)

1:21

Pregnancy and Sexual Health : How to Test Male Fertility

ehowhealth/YouTube

4:02

Male Infertility Expert Answers Common Questions

UC San Diego Health/YouTube

40:20

Improving Fertility in Men with Poor Sperm Count | Jesse Mills, MD | UCLAMDChat

UCLA Health/YouTube

51:40

Optimizing Male Fertility | Jesse Mills, MD | UCLAMDChat

UCLA Health/YouTube

4:30

How to read a semen analysis | Infertility TV

Infertility TV/YouTube

20:45

Semen Analysis

LabsforLifeProject/YouTube

2:14

Fertility Semen Analysis • WCWRC

West Coast Women's Reproductive Center/YouTube

4:07

Semen Analysis Test Lab | Sperm Morphology

ThomasTKtungnung/YouTube

8:54

Semen Analysis: Boyz Under the Hood

InfertilityChannel/YouTube

4:32

Low or Abnormal Semen

Center for Human Reproduction/YouTube

Semen Analysis

Semen Analysis

Also called: Spermogram, Sperm Analysis, Sperm Count, Seminal Fluid Analysis, Semen Testing, Male Fertility Test

A semen analysis measures the quantity and quality of a man's semen and sperm. A low sperm count or abnormal sperm shape or movement can make it difficult for a man to make a woman pregnant. The test is used to help find the cause of male infertility.

Semen Analysis

Also called: Spermogram, Sperm Analysis, Sperm Count, Seminal Fluid Analysis, Semen Testing, Male Fertility Test

A semen analysis measures the quantity and quality of a man's semen and sperm. A low sperm count or abnormal sperm shape or movement can make it difficult for a man to make a woman pregnant. The test is used to help find the cause of male infertility.

{"label":"Volume of Semen Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"mL","code":"mL","name":"milliliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":1.5},"text":"Decreased volume of seminal fluid may indicate fewer sperm, consequently diminishing opportunities for a successful fertilization.","conditions":["Low sperm volume"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":1.5,"max":5},"text":"The standard amount of seminal fluid collected is between 1.5 and 5 milliliters (about a teaspoon) per ejaculation.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":5,"max":10},"text":"Excessive seminal fluid may dilute the concentration of sperm.","conditions":[]}],"value":3.3}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
mL
1.5
5
Your result is Normal.
The standard amount of seminal fluid collected is between 1.5 and 5 milliliters (about a teaspoon) per ejaculation.
Related conditions
{"label":"Semen Liquification Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"min","code":"min","name":"minute"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":60},"text":"The semen should initially be thick and then liquefy within 15 to 20 minutes, and up to 60 minutes after the collection. ","conditions":[]},{"flag":"abnormal","label":{"short":"Increased","long":"Increased","orientation":"horizontal"},"values":{"min":60,"max":120},"text":"If liquefaction of the semen does not occur during the first 60 minutes, then it may impede sperm movement.","conditions":["Impaired sperm mobility"]}],"value":30}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
min
60
Your result is Normal.
The semen should initially be thick and then liquefy within 15 to 20 minutes, and up to 60 minutes after the collection.
Related conditions
{"label":"Sperm Concentration Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"(10<sup>6<\/sup>)\/mL","code":"10*6\/mL","name":"million per milliliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":20},"text":"Fewer sperm and\/or a lower sperm concentration may impair fertility.","conditions":[]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":20,"max":80},"text":"Normal sperm concentration is at least 20 million or more sperm per milliliter of semen, with a total ejaculate volume of 80 million or more sperm.","conditions":[]}],"value":50}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
(10<sup>6</sup>)/mL
20
Your result is Normal.
Normal sperm concentration is at least 20 million or more sperm per milliliter of semen, with a total ejaculate volume of 80 million or more sperm.
Related conditions
{"label":"Sperm Motility Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"%","code":"%","name":"percent"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":40},"text":"A lower number may indicate that there is toxin exposure such as smoking, alcohol, caffeine, or chemicals. Low motility can also indicate hormonal problems or a varicocele (varicose veins in the scrotum).","conditions":["Asthenozoospermia"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":40,"max":100},"text":"If at least 40% of the sperm in a sample are moving, this is considered normal sperm motility.","conditions":[]}],"value":70}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
%
40
Your result is Normal.
If at least 40% of the sperm in a sample are moving, this is considered normal sperm motility.
Related conditions
{"label":"Sperm Morphology Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"%","code":"%","name":"percent"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":4},"text":"Severe impairment or probable inability to fertilize.","conditions":[]},{"flag":"borderline","label":{"short":"P","long":"Poor","orientation":"horizontal"},"values":{"min":4,"max":10},"text":"Possibly decreased or impaired fertilizing capacity.","conditions":[]},{"flag":"normal","label":{"short":"G","long":"Good","orientation":"horizontal"},"values":{"min":10,"max":14},"text":"Indicates good fertility potential.","conditions":[]},{"flag":"normal","label":{"short":"E","long":"Excellent","orientation":"horizontal"},"values":{"min":14,"max":60},"text":"Indicates excellent fertilizing capacity.","conditions":[]}],"value":12}[{"abnormal":0},{"borderline":0},{"normal":0},{"normal":1}]
Use the slider below to see how your results affect your health.
%
4
10
14
Your result is Good.
Indicates good fertility potential.
Related conditions
{"label":"Semen PH Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"pH","code":"[pH]","name":"pH"}],"items":[{"flag":"abnormal","label":{"short":"Acidic pH","long":"Acidic pH","orientation":"horizontal"},"values":{"min":3,"max":7.2},"text":"Acidic ejaculate (lower pH value) may indicate one or both of the seminal vesicles are blocked.","conditions":["Ejaculatory duct obstruction or congenital bilateral","Absence of the vas deferens"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":7.2,"max":14},"text":" Semen pH increases with time, so high pH values may provide little clinically useful information. ","conditions":[]}],"value":10.6}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
pH
7.2
Your result is Normal.
Semen pH increases with time, so high pH values may provide little clinically useful information.
Related conditions
{"label":"Seminal Fructose Levels Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"\u03bcmol","code":"umol","name":"micromole"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":13},"text":"Fructose level in the semen may be analyzed to determine the amount of energy available to the semen for moving. Absence of fructose may indicate a problem.","conditions":["Ejaculatory duct obstruction,","Bilateral congenital absence of the vas deferens","Partial retrograde ejaculation","Androgen deficiency"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":13,"max":100},"text":"A normal fructose level in the semen indicates there is enough energy available for the sperms to move.","conditions":[]}],"value":56.5}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
μmol
13
Your result is Normal.
A normal fructose level in the semen indicates there is enough energy available for the sperms to move.
Related conditions
{"label":"White Blood Cells in Semen Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"(10<sup>6<\/sup>)\/mL","code":"10*6\/mL","name":"million per milliliter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":1000000},"text":"When it comes to white blood cells in your semen, the fewer the better.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":1000000,"max":3000000},"text":"A high count of white blood cells is a sign of inflammation in the semen and may negatively impact sperm function.","conditions":["Leukocytospermia"]}],"value":500000}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
(10<sup>6</sup>)/mL
1000000
Your result is Normal.
When it comes to white blood cells in your semen, the fewer the better.
Related conditions
{"label":"Sperm Vitality Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"%","code":"%","name":"percent"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":58},"text":"This indicates there is an elevated number of dead sperms in your seminal sample.","conditions":["Necrozoospermia"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":58,"max":100},"text":"There\u00a0should be over 58% living sperms to be considered as a normal sample.","conditions":[]}],"value":79}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
%
58
Your result is Normal.
There should be over 58% living sperms to be considered as a normal sample.
Related conditions
{"label":"Sperm Number Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"\/10<sup>6<.sup>","code":"\/10*6","name":"per million"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":40000000},"text":"The absence or low number of sperms in the seminal sample can indicate a wide variety of problems.","conditions":["Cryptozoospermia","Azoospermia"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":40000000,"max":80000000},"text":" There\u00a0should be over 40 million sperms per ejaculate.","conditions":[]}],"value":60000000}[{"abnormal":0},{"normal":0}]
Use the slider below to see how your results affect your health.
/10<sup>6<.sup>
40000000
Your result is Normal.
There should be over 40 million sperms per ejaculate.
Related conditions
{"label":"Sperm Appearance Reference Range","scale":"lin","step":0.25,"hideunits":true,"items":[{"flag":"normal","label":{"short":"Grey-opalescent","long":"Grey-opalescent","orientation":"horizontal"},"values":{"min":0,"max":1},"text":"A normal semen sample has a homogeneous, grey-opalescent color.","conditions":[]},{"flag":"abnormal","label":{"short":"Any other color","long":"Any other color","orientation":"horizontal"},"values":{"min":1,"max":2},"text":"An opaque gray color may indicate the sperm concentration is very low. A red-brown color is suggestive of the presence of red blood cells (blood). A yellow color may be indicative of jaundice or intake of certain vitamins or drugs.","conditions":["Haemospermia","Low sperm concentration","Jaundice"]}],"value":0.5}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
Your result is Grey-opalescent.
A normal semen sample has a homogeneous, grey-opalescent color.
Related conditions
You may need a semen analysis if:
- You and your partner have been trying to have a baby for at least 12 months without success.
- You've recently had a vasectomy and need to make sure that you don't have any sperm in your semen.
You will need to provide a semen sample. For accurate the results, the semen must be examined quickly before the sperm begin to die. For this reason, you will usually provide a sample in a private room at a lab by masturbating and collecting your semen in a sterile container. You may be asked to urinate (pee) and wash your hands and penis before collecting your sample. This will help keep bacteria from your skin out of the sample.
To get accurate results:
- Don't use lubricants or saliva because they could harm your sperm.
- Make sure to collect all the semen you produce. If you miss collecting even a bit of it, you should let your provider know.
If you prefer, you may be able to collect your sample at home during sex by using a special type of condom that your provider gives you. But you will have to keep the sample at body temperature and take it to the lab within 30 to 60 minutes after collecting it.
You may need to provide two or more semen samples within a week or two. That's because your sperm count and semen quality can vary from day to day. Talk with your provider if you have questions or concerns about providing a semen sample.
Results to check fertility:
Your semen analysis will include many measurements that describe your semen and sperm:
- Volume is the amount of semen in your sample. A low volume may cause infertility.
- Sperm count is the number of sperm in the entire sample. A low count may make it difficult to get your partner pregnant.
- Sperm concentration measures how close together the sperm are in your semen. A low concentration may be a sign of a problem.
- Sperm movement (motility) tells you the percentage of sperm that are moving forward. Sperm must be able to move forward to fertilize an egg.
- Sperm shape (morphology) is the number of sperm that have a normal shape. Sperm with abnormal shapes may not be able to fertilize an egg.
- pH describes the acidity of your semen. Abnormal acidity can kill sperm or affect their ability to move.
- White blood cells (leukocytes) in sperm may be a sign that an infection is affecting your fertility.
If your semen analysis results aren't all normal, it doesn't mean you're permanently infertile. But it does show that your sperm may be part of the problem you and your partner are having getting pregnant.
Your provider may order more tests to help find the cause of the problem so it can be treated. There are many possible causes, including:
- Certain habits you may be able to change, such as smoking
- A physical problem in your testicles, such as an enlarged vein (varicocele)
- Certain genetic disorders or other health conditions, including hormone disorders, diabetes, and cystic fibrosis
Treatments for infertility depend on the cause. To help improve your chances of having a baby, your provider may refer you to a doctor who specializes in infertility.
Results for semen analysis to check a vasectomy:
The results of your semen analysis will tell you if there's any sperm in your semen. It's not unusual to find sperm in several ejaculations after a successful vasectomy.
- If sperm is found, you'll need repeat testing until your sample has no sperm. In the meantime, you and your partner will have to use other birth control to prevent pregnancy.
- If no sperm is found, you and your partner should be able to stop using other forms of birth control.
1. Semen Analysis: MedlinePlus Lab Test Information [accessed on Dec 20, 2018]
2. http://apps.who.int/iris/bitstream/handle/10665/44261/9789241547789_eng.pdf;jsessionid=572C217186D954117C5F1E768D8CF7A4?sequence=1 [accessed on Dec 20, 2018]
3. Semen Analysis (Sperm Count Testing) | myVMC [accessed on Dec 20, 2018]
4. 519114: Semen Analysis, Basic | LabCorp [accessed on Dec 20, 2018]

Additional Materials (9)

Example of spermazoo and spermazoo karyogram

Example of spermazoo and spermazoo karyogram

Image by AGeremia

Slides containing a semen sample for analysis

The slides allow medical laboratory technicians to view the sample under a microscope and garner the results of a fertility analysis manually as well as cross-check the accuracy of the analysis machine.

Image by U.S. Air

Semen Component

Image of a test tube with the components of semen separated by volume from various glands. The majority of semen is seminal plasma, which accounts for 95% with secretions from the seminal vesicles, prostate gland, and bulbourethral (Cowper's) gland; sperm produced in the testicles make up the remaining 5% of semen volume. The seminal vesicles contribute most of the volume of ejaculate (60%) in the form of seminal fluid; one of the most important components of the seminal fluid is fructose, a sweet-tasting natural sugar which provides energy for the sperm on their long journey to the fallopian tubes. The secretions from the prostate make up the next largest portion of the ejaculate (30%) and include prostaglandin and other supportive compounds such as immunoglobins; prostaglandin actually causes uterine contraction-which may aid in the uptake of sperm. The bulbourethral glands contribute the remaining volume of the ejaculate (5%) which includes mucin, a potent basic buffer designed to counter the hostile acidic environment of the vagina.

Image by TheVisualMD

Sensitive content

This media may include sensitive content

Prostate and Seminal Vesicles with Penis and Testicles

Prostate cancer is a malignant growth in the prostate, a walnut-sized gland found only in men that helps produce semen. Some prostate cancers are aggressive, but many grow slowly and may never metastasize (spread). In the US, prostate cancer is the second leading cause of cancer death among men, after lung cancer. One in six men will be diagnosed with prostate cancer during his lifetime, and one man in 35 will die of the disease. But the death rate for prostate cancer is decreasing, and the disease is being diagnosed earlier as well.

Image by TheVisualMD

Semen Contents in Glass Vial

Semen is mostly composed of seminal fluid (60%) and prostatic fluid (30%). The remainder is composed of sperm (5%) and bulbourethral fluid (5%).

Image by TheVisualMD

Hematospermia

Video by mdconversation/YouTube

How to read a semen analysis | Infertility TV

Video by Infertility TV/YouTube

Semen Analysis: Boyz Under the Hood

Video by InfertilityChannel/YouTube

The Male Biological Clock

Video by SciShow/YouTube

Example of spermazoo and spermazoo karyogram

AGeremia

Slides containing a semen sample for analysis

U.S. Air

Semen Component

TheVisualMD

Sensitive content

This media may include sensitive content

Prostate and Seminal Vesicles with Penis and Testicles

TheVisualMD

Semen Contents in Glass Vial

TheVisualMD

19:07

Hematospermia

mdconversation/YouTube

4:30

How to read a semen analysis | Infertility TV

Infertility TV/YouTube

8:54

Semen Analysis: Boyz Under the Hood

InfertilityChannel/YouTube

3:14

The Male Biological Clock

SciShow/YouTube

Testosterone

Testosterone

Also called: Testosterone Levels, Serum Testosterone, Testosterone, Total

A testosterone levels test measures the amount of the hormone testosterone in a sample of your blood. Testosterone is the main sex hormone in men. Women also have testosterone in their bodies, but in much smaller amounts. Low or high levels may be a sign of a health problem.

Testosterone

Also called: Testosterone Levels, Serum Testosterone, Testosterone, Total

A testosterone levels test measures the amount of the hormone testosterone in a sample of your blood. Testosterone is the main sex hormone in men. Women also have testosterone in their bodies, but in much smaller amounts. Low or high levels may be a sign of a health problem.

{"label":"Testosterone, Total Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":264},"text":"Low levels of testosterone can happen as a result of several health problems; and can lead to low sperm count, erectile dysfunction, and drop in sex drive, among others.","conditions":["Infertility","Erectile Dysfunction","Decreased Sex Drive","Hypothalamus Disorders","Pituitary Disorders"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":264,"max":916},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":916,"max":1500},"text":"High levels of testosterone can be the result of certain health problems. Talk to your doctor to know what your results mean in your specific case. ","conditions":["Early Puberty","Testicular Tumors","Congenital Adrenal Hyperplasia","Hypothalamus Disorders"]}],"value":590}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
264
916
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
{"label":"Testosterone, Bioavailable Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":40},"text":"Your levels of bioavailable testosterone are low. Talk to your doctor to know what this means in your specific case. ","conditions":["Hypogonadism","Testicular failure","Testicular trauma","Testicular ischemia","Infections","Autoimmune diseases","Metabolic disorders","Orchidectomy","Disorders of hypothalamus and pituitary\u00a0gland","Head trauma","Malnutrition","Excessive exercise"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":40,"max":250},"text":"Normal levels may slightly vary from laboratory to laboratory.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":250,"max":500},"text":"Your levels of bioavailable testosterone are high. Talk to your doctor to know what this means in your specific case. ","conditions":["Precocious puberty","Testicular tumors","Adrenal tumors","Androgen abuse","Congenital adrenal hyperplasia"]}],"value":145}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
40
250
Your result is Normal.
Normal levels may slightly vary from laboratory to laboratory.
Related conditions
{"label":"Testosterone, Free Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"pg\/mL","code":"pg\/mL","name":"picogram per milliliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":9.3},"text":"Low levels of free testosterone can be the result of certain health problems. Talk to your doctor to know what your results mean in your specific case.","conditions":["Infertility","Erectile Dysfunction","Decreased Sex Drive","Hypothalamus Disorders","Pituitary Disorders"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":9.3,"max":26.5},"text":"The concentration of free testosterone is very low, typically <2% of the total testosterone concentration.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":26.5,"max":50},"text":"High levels of free testosterone can be the result of certain health problems. Talk to your doctor to know what your results mean in your specific case. ","conditions":["Early Puberty","Testicular Tumors","Congenital Adrenal Hyperplasia","Hypothalamus Disorders"]}],"value":17.9}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
pg/mL
9.3
26.5
Your result is Normal.
Related conditions
A testosterone levels test measures the amount of testosterone in a sample of your blood. Testosterone is known as a "male" sex hormone, but females have testosterone in smaller amounts.
Testosterone is made by:
- The testicles (or testes), the part of the male reproductive system that makes sperm
- The ovaries, the part of the female reproductive system that makes eggs
- The adrenal glands, organs on top of each kidney that make several hormones
During male puberty, testosterone causes body hair, muscle growth, and a deepening voice. In adult life, it controls sex drive, maintains muscle mass, and helps make sperm. In females, testosterone is important for the growth of bones and muscles, and healthy organs.
There are different forms of testosterone in your blood that may be measured to help diagnose certain health problems. Most of your testosterone is attached to proteins. The proteins prevent your tissues from using the testosterone right away, which helps control the amount of "active" testosterone in your body. Testosterone that's not attached to proteins is called free testosterone. Free testosterone acts on your tissues.
Three types of blood tests measure these different forms of testosterone:
- A total testosterone test measures free testosterone and testosterone that's attached to proteins. This is the most common type of test.
- A free testosterone test measures only the "active" form of testosterone. This test is less common, but it may be useful for diagnosing certain medical conditions.
- A bioavailable testosterone test measures free testosterone and testosterone that's loosely attached to a blood protein called albumin. This test isn't commonly done. But like a free testosterone test, it may help diagnose certain medical conditions.
A testosterone levels test may be used with other tests to help:
- Diagnose the cause of symptoms that could be from testosterone levels that are too high or too low
- In children and teens, to find out what's causing:
  Early puberty
  Delayed puberty
Testosterone testing is also used to monitor your health if you:
- Have had an abnormal testosterone test in the past
- Are taking medicine that may affect your testosterone levels
- Are a transgender man taking testosterone for masculinizing hormone therapy (also called gender-affirming hormone therapy)
You may need this test if you have symptoms of abnormal testosterone levels.
For males who have gone through puberty, the test is mostly used for symptoms of low T levels (testosterone levels which are too low). Testosterone levels tend to decrease with age. But other health issues may also cause low T, such as thyroid problems, long-lasting illness, or problems with the testicles.
The symptoms of low T may include:
- Low sex drive
- Erectile disfunction or "ED" (difficulty getting an erection)
- Infertility (difficulty getting someone pregnant)
- Enlarged breasts
- Lack of face or body hair
- Thinning bones or anemia without a known cause
- Loss of muscle mass
For females, the test is mostly used for symptoms of high T levels, such as:
- Abnormal hair growth on the body or face
- Hair loss on the head that may be like male-pattern baldness (hair loss at the temples and balding on the top of the head)
- A voice that gets lower
- Irregular or no menstrual periods
- Infertility (difficulty getting pregnant)
- Acne
Your test results may mean different things depending on which test was done, your age, your symptoms, the results of other tests, and other conditions you may have. So, it's best ask your provider to explain your test results.
A testosterone level test alone can't diagnose any health conditions, but abnormal results with symptoms may be a sign of a health problem.
- In males, low T levels may be caused by different conditions, including:
  Chronic (long-lasting) diseases such as liver, or kidney disease
  A pituitary gland disorder
  Benign tumors (not cancer)
  Injury to the testicles
  Alcohol use disorder
  Certain genetic diseases such as Klinefelter syndrome
- In females low T levels are normal, but extremely low levels may be a sign of:
  An adrenal gland disorder
  A pituitary gland disorder
  An ovarian disorder
- In males, high T levels may be caused by:
  A tumor in the testicles
  Steroid use
  An adrenal gland disorder, such as congenital adrenal hyperplasia (CAH)
- In females, high T levels may be caused by:
  Polycystic ovary syndrome (PCOS)
  Ovarian cancer
  An adrenal gland disorder, such as congenital adrenal hyperplasia (CAH)
  A disorder of the pituitary gland
If your results are not normal, it doesn't always mean you have a medical condition that needs treatment. It's normal for testosterone levels to decrease with age. And certain medicines can affect your results. If you have questions about your results, talk to your health care provider.
Learn more about laboratory tests, reference ranges, and understanding results.
1. Testosterone | LabCorp [accessed on Oct 02, 2018]
2. 004226: Testosterone, Total | LabCorp [accessed on Oct 02, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (16)

Male Endocrine System

3D visualization reconstructed from scanned human data of the male endocrine system. The Leydig cells of the testis produces the main male sex hormone, testosterone. Testosterone facilitates sexual maturity of the male, production of sperm and secondary sex characteristics such as hair growth and voice modulation.

Image by TheVisualMD

Testosterone, Testicle

The testes are the male gonads, and perform two functions: to manufacture motile sperm and produce male sex hormones, namely testosterone. Testosterone is the principal sex hormone in males, responsible for the maturation of sex organs and production of sperm, as well as secondary sexual characteristics such as growth of body and facial hair, increased muscle mass, and a deeper voice; Testosterone is produced in the testes by Leydig cells. Production of the hormone is high during the fetal and neonatal period, when testosterone is needed for the development of male genitalia. Production then declines until puberty, when it increases dramatically.

Image by TheVisualMD

Sensitive content

This media may include sensitive content

Testosterone: Male Reproductive System

Testosterone is responsible for the development of secondary sexual characteristics, including a deeper voice, increased muscle mass and strength and the growth of body and facial hair; testosterone also affects fat distribution and maintains bone density.

Image by TheVisualMD

Testosterone: Muscles

Anabolic effects of testosterone include growth of muscle mass, which is caused by testosterone increasing the muscle's protein synthesis.

Image by TheVisualMD

Sensitive content

This media may include sensitive content

Testis with Exposed Internal Structure

3D visualization based on segmented human data of a testis. Leydig cells, which reside in the testis, produce male sex hormones called androgens. Of these, testosterone is responsible for the development of secondary sexual characteristics and the maintenance of the sperm development sites.

Image by TheVisualMD

Leydig Cell of Testis

Visualization of the Leydig cells of the testis. Leydig cells are the principal cell type interspersed in the interstitial space between the seminiferous tubules. They are responsible for the synthesis and secretion of male sex hormones and other non-steroid substances. The main hormone, testosterone is responsible for the development of secondary sexual characteristics and the maintenance of the sperm development sites.

Image by TheVisualMD

testicle

How the testicles work from the inside.

Image by OpenStax College

Arnold Schwarzenegger before defending the title for his fifth Mr. Olympia contest in 1974

Arnold Schwarzenegger before defending the title for his fifth Mr. Olympia contest in 1974

Image by Madison Square Garden Center

Testosterone Molecule

Medical visualization of a testosterone molecule. Testosterone, as with all of the other main sex hormones, is a steroid hormone derived from cholesterol. Along with dihydrotestosterone, testosterone is one of the most important male sex hormones. Testosterone production is primarily located in leydig cells in the testes. Smaller amounts are produced by other tissues such as the adrenal cortex and by the ovaries and placenta in women. Testosterone is responsible for male secondary sexual characteristics such as facial hair and deepening of the voice, as well as sperm production. As with all sex hormones, the effects of testosterone aren't limited to reproduction; testosterone affects muscle and bone growth and is involved with the production of red blood cells. Both men and women have all of the main sex hormones, but in very different amounts. Men have much more testosterone than men, but testosterone is essential for women, too.

Image by TheVisualMD

Testosterone Molecule

Medical visualization of a testosterone molecule. Testosterone, as with all of the other main sex hormones, is a steroid hormone derived from cholesterol. Along with dihydrotestosterone, testosterone is one of the most important male sex hormones. Testosterone production is primarily located in leydig cells in the testes. Smaller amounts are produced by other tissues such as the adrenal cortex and by the ovaries and placenta in women. Testosterone is responsible for male secondary sexual characteristics such as facial hair and deepening of the voice, as well as sperm production. As with all sex hormones, the effects of testosterone aren't limited to reproduction; testosterone affects muscle and bone growth and is involved with the production of red blood cells. Both men and women have all of the main sex hormones, but in very different amounts. Men have much more testosterone than women, but testosterone is essential for women, too.

Image by TheVisualMD

This browser does not support the video element.

Testosterone Testing in Men

Testosterone Testing in Men: Testosterone is the male sex hormone. It helps to create sperm, incites the male libido, and ushers boys into puberty. Produced in the testes, levels of testosterone naturally fluctuate throughout the day. Low testosterone levels, however, can have negative effects such as reduced libido, causing erectile dysfunction, depression, and reduced bone density. The main causes of low testosterone are aging (andropause), hypogonadism, certain diseases, excess body fat, or the use of morphine or anabolic steroids. If you feel you may suffer from low testosterone, a simple blood test can be used to diagnose the condition and to find out what is causing it. Treatment options include testosterone replacement therapy, gels, patches, and gum.

Video by TheVisualMD

How To Free Up Your Testosterone

Video by ProgradeNutrition/YouTube

Low testosterone: symptoms, diagnosis and treatment | Ohio State Medical Center

Video by Ohio State Wexner Medical Center/YouTube

Low Testosterone, Symptoms & Treatments - Dr. Sam Chawla

Video by WakeMed Health & Hospitals/YouTube

Low T - Health Risks of Testosterone Therapy - Mayo Clinic

Video by Mayo Clinic/YouTube

Testosterone Therapy and Cardiovascular Risk

Video by Mayo Proceedings/YouTube

Male Endocrine System

TheVisualMD

Testosterone, Testicle

TheVisualMD

Sensitive content

This media may include sensitive content

Testosterone: Male Reproductive System

TheVisualMD

Testosterone: Muscles

TheVisualMD

Sensitive content

This media may include sensitive content

Testis with Exposed Internal Structure

TheVisualMD

Leydig Cell of Testis

TheVisualMD

testicle

OpenStax College

Arnold Schwarzenegger before defending the title for his fifth Mr. Olympia contest in 1974

Madison Square Garden Center

Testosterone Molecule

TheVisualMD

Testosterone Molecule

TheVisualMD

3:02

Testosterone Testing in Men

TheVisualMD

3:00

How To Free Up Your Testosterone

ProgradeNutrition/YouTube

3:19

Low testosterone: symptoms, diagnosis and treatment | Ohio State Medical Center

Ohio State Wexner Medical Center/YouTube

2:37

Low Testosterone, Symptoms & Treatments - Dr. Sam Chawla

WakeMed Health & Hospitals/YouTube

1:07

Low T - Health Risks of Testosterone Therapy - Mayo Clinic

Mayo Clinic/YouTube

8:07

Testosterone Therapy and Cardiovascular Risk

Mayo Proceedings/YouTube

Thyroid Tests

Thyroid Tests

Also called: Thyroid Function Tests, Thyroid Studies, Thyroid Panel

Thyroid tests check how well your thyroid is working. They are also used to diagnose and help find the cause of thyroid diseases such as hyperthyroidism and hypothyroidism. Thyroid tests include blood tests and imaging tests.

Thyroid Tests

Also called: Thyroid Function Tests, Thyroid Studies, Thyroid Panel

Thyroid tests check how well your thyroid is working. They are also used to diagnose and help find the cause of thyroid diseases such as hyperthyroidism and hypothyroidism. Thyroid tests include blood tests and imaging tests.

Health care professionals use thyroid tests to check how well your thyroid is working and to find the cause of problems such as hyperthyroidism or hypothyroidism. The thyroid is a small, butterfly-shaped gland in the front of your neck that makes two thyroid hormones: thyroxine (T₄) and triiodothyronine (T₃). Thyroid hormones control how the body uses energy, so they affect nearly every organ in your body, even your heart.
Thyroid tests help health care professionals diagnose thyroid diseases such as
- hyperthyroidism—when thyroid hormone levels are too high
- Graves’ disease, the most common cause of hyperthyroidism
- hypothyroidism—when thyroid hormones levels are too low
- Hashimoto’s disease, of the most common cause of hypothyroidism
- thyroid nodules and thyroid cancer
Your doctor will start with blood tests and may also order imaging tests.
1. Thyroid Diseases [accessed on Oct 03, 2018]

Additional Materials (19)

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Woman With Goiter Due to Hypothyroidism

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. A goiter is any visible enlargement of the thyroid gland. In the past, goiters were often due to a lack of iodine in the diet (iodized salt has greatly reduced such goiters). Goiters can be present in cases of either hormone overproduction (hyperthyroidism) or underproduction (hypothyroidism).

Image by TheVisualMD

Thyroid Disease in Women

Document by Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Document by Office on Women's Health, U.S. Department of Health and Human Services

Document by Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

The thyroid gland’s production of thyroid hormones (T3 and T4) is regulated by thyroid-stimulating hormone (TSH), which is made by the pituitary gland.

Image by NIDDK Image Library

Thyroid Gland

The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Image by CNX Openstax

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which play key roles in regulating many aspects of metabolism, the rate at which the cells use energy and carry out chemical processes. The thyroid and the hormones it produces are under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland.

Image by TheVisualMD

Thyroid Gland

Image by CFCF

Setting the Pace: Thyroid & Metabolism

Image by TheVisualMD

Thyroid Blood Tests

Video by Tom Wade MD/YouTube

Thyroid Function tests - what your results can mean

Video by Pathology Tests Explained/YouTube

Understanding Thyroid Function Tests

Video by AdonaiDEC/YouTube

Thyroid Gland, Hormones and Thyroid Problems, Animation

Video by Alila Medical Media/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

Thyroid Gland - Thyroid Hormones

Video by Armando Hasudungan/YouTube

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Woman's neck region with visible thyroid

TheVisualMD

Woman With Goiter Due to Hypothyroidism

TheVisualMD

Thyroid Disease in Women

Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Office on Women's Health, U.S. Department of Health and Human Services

Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

NIDDK Image Library

Thyroid Gland

CNX Openstax

Thyroid Gland

TheVisualMD

Thyroid Gland

CFCF

Setting the Pace: Thyroid & Metabolism

TheVisualMD

6:57

Thyroid Blood Tests

Tom Wade MD/YouTube

3:12

Thyroid Function tests - what your results can mean

Pathology Tests Explained/YouTube

6:07

Understanding Thyroid Function Tests

AdonaiDEC/YouTube

4:03

Thyroid Gland, Hormones and Thyroid Problems, Animation

Alila Medical Media/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

12:47

Thyroid Gland - Thyroid Hormones

Armando Hasudungan/YouTube

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

TSH (Thyroid-Stimulating Hormone) Test

TSH (Thyroid-Stimulating Hormone) Test

Also called: TSH, Thyroid-Stimulating Hormone, Thyrotropin

The test measures the amount of thyroid-stimulating hormone (TSH) in a sample of your blood. TSH is made in the pituitary gland and stimulates the release of thyroid hormone. If your TSH levels are too high or too low, it can indicate a thyroid disorder.

TSH (Thyroid-Stimulating Hormone) Test

Also called: TSH, Thyroid-Stimulating Hormone, Thyrotropin

The test measures the amount of thyroid-stimulating hormone (TSH) in a sample of your blood. TSH is made in the pituitary gland and stimulates the release of thyroid hormone. If your TSH levels are too high or too low, it can indicate a thyroid disorder.

{"scale":"lin","step":0.1,"hideunits":false,"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":0.45},"text":"A low TSH level usually indicates that the thyroid is producing too much thyroid hormone (hyperthyroidism). Occasionally, a low TSH may result from an abnormality in the pituitary gland, which prevents it from making enough TSH to stimulate the thyroid (central hypothyroidism)."},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0.45,"max":4.5},"text":"The pituitary gland releases TSH into the blood to stimulate the thyroid to make more thyroid hormone. The amount of TSH that the pituitary sends into the bloodstream depends on the amount of thyroid hormone in the body. In most healthy individuals, a normal TSH value means that the thyroid is functioning properly."},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":4.5,"max":10},"text":"A high TSH level indicates that the thyroid gland is not making enough thyroid hormone (hypothyroidism)."}],"units":[{"printSymbol":"(mi.U.)\/mL","code":"m[IU]\/mL","name":"milli international unit per milliliter"}],"disclaimer":"Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are \"within normal limits.\""}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
(mi.U.)/mL
0.45
4.5
Your result is Low.
A low TSH level usually indicates that the thyroid is producing too much thyroid hormone (hyperthyroidism). Occasionally, a low TSH may result from an abnormality in the pituitary gland, which prevents it from making enough TSH to stimulate the thyroid (central hypothyroidism).
Related conditions
You may need a TSH test if you have symptoms of too much or too little thyroid hormone in your blood.
Hyperthyroidism (too much thyroid hormone) is also called overactive thyroid. Having more thyroid hormones than you need speeds up your body functions and causes symptoms that include:
- Weight loss, even though you may be eating more than usual
- Rapid or irregular heartbeat
- Feeling nervous or irritable
- Trouble sleeping, fatigue
- Shaky hands, muscle weakness
- Sweating or being very sensitive to heat
- Frequent bowel movements (pooping a lot)
- Goiter (enlarged thyroid)
Hypothyroidism (too little thyroid hormone) is also called underactive thyroid. Not having enough thyroid hormone slows down your body functions and causes symptoms that include:
- Fatigue
- Weight gain
- Being very sensitive to cold
- Joint and muscle pain
- Dry skin
- Dry, thinning hair
- Heavy or irregular menstrual periods
- Depression
- Constipation
You may also have a TSH test, along with other tests, to help diagnose unusual bumps or lumps on your thyroid that may be thyroid cancer or thyroid nodules (growths on your thyroid that aren't cancer).
Your TSH test results can tell you if your thyroid is making too much or too little thyroid. But the test can't explain why your TSH levels may be too high or too low.
If your test results aren't normal, your provider will probably order other thyroid blood tests to find out what's causing your thyroid problem. These blood tests may include:
- T4 thyroid hormone test
- T3 thyroid hormone test
- Thyroid antibodies test to help diagnose an autoimmune thyroid disorder, such as:
  Graves' disease, the most common cause of hyperthyroidism
  Hashimoto's disease, that the most common cause of hypothyroidism
In certain cases, an abnormal TSH result may be a sign of a pituitary gland problem, but this doesn't happen often.
1. 004259: Thyroid-stimulating Hormone (TSH) | LabCorp [accessed on Oct 04, 2018]
2. TSH test: MedlinePlus Medical Encyclopedia [accessed on Oct 04, 2018]
3. TSH [accessed on Oct 04, 2018]
4. 004593: Thyroid-stimulating Hormone (TSH) in Pregnancy | LabCorp [accessed on Oct 04, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (28)

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which play key roles in regulating many aspects of metabolism, the rate at which the cells use energy and carry out chemical processes. The thyroid and the hormones it produces are under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland.

Image by TheVisualMD

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Thyroid Gland

Image by CFCF

Follicular Cell of Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3). The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid contains spherical follicles that absorb iodine ions from the blood for use in the production of T4 and T3. Iodine deficiency, rare in the U.S., affects two billion people worldwide and is the leading preventable cause of mental retardation.

Image by TheVisualMD

Woman with visible Brain revealing Pituitary Gland

The pituitary gland is a pea-sized endocrine gland located at the base of the skull, between the optic nerves. It is often referred to as the endocrine system's \"master gland\" because it regulates the activities of other glands. The pituitary, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when. The pituitary governs testosterone and estrogen production, as well as ovulation and breast milk production; it also helps regulate growth, blood pressure, maintain proper fluid balance, and other aspects of metabolism.

Image by TheVisualMD

Follicle-stimulating hormone

Follicle-stimulating hormone

Image by MartaFF

Follicle-stimulating hormone

The time scale starts with the (LMP), given as day number. Day number 1 corresponds to 0 to 0.99 days from LMP, and Day number 2 corresponds to 1.00 to 1.99 days from LMP and so forth. The time scale ends at whatever is the actual next menstruation, which marks the beginning of the next cycle, which is equivalent to starting all over again from the beginning of the time scale.

Image by Mikael Haggstrom

hCG testing for pregnancy

Diagram of typical immunoassay home pregnancy test which detects human chorionic gonadotropin (hCG). (A) A urine sample is applied to the stick. If pregnant, this should contain hCG. (B) As the sample is absorbed into the stick it goes through free dye-labeled antibodies that recognize and stick to hCG. (C) An anchored set of antibodies stick to and capture hCG molecules (and the attached dye-labeled antibodies), creating the first line. In the "not pregnant" sample no hCG is attached to the dye-labeled antibodies, so they wash past this point and no line appears. (D) A second anchored set of antibodies captures the dye-labeled antibodies, providing a positive control to indicate that the test is working properly.

Image by Madprime

The classic finding of exophthalmos and lid retraction in Graves' disease

Proptosis and Lid Retraction from Graves Disease : Photograph showing a classic finding of Graves' Disease, proptosis and lid retraction.

Image by Jonathan Trobe, M.D. - University of Michigan Kellogg Eye Center

What are the symptoms of Graves' disease?

Graves' disease symptoms

Image by Original uploader was Madhero88 at en.wikipedia

What is Graves' ophthalmopathy?

Magnetic Resonance Imaging of the orbits, showing congestion of the retro-orbital space and enlargement of the extraocular muscles (arrows), consistent with the diagnosis of Graves' Ophthalmopathy.

Image by Huy A Tran and Glenn EM Reeves

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam`s apple. Hormones produced by the thyroid gland have an enormous impact on many aspects of metabolism.

Image by TheVisualMD

Thyroid Stimulating Hormone

A Classic Negative Feedback Loop

Image by OpenStax College

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Woman with Visible Thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3). The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid and the hormones it produces are under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland, which is often referred to as the \"master gland\" because it regulates the activities of other endocrine glands.

Image by TheVisualMD

Thyroid Stimulating Hormone (TSH)

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces hormones that help maintain body temperature, heart rate, moods, and metabolism. Hyperthyroidism (when too much hormone is produced) is often caused by an autoimmune disorder called Graves' disease, in which antibodies produced by the immune system over-stimulate the thyroid. The production of thyroid hormones is under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland.

Image by TheVisualMD

Woman With Goiter Due to Hypothyroidism

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. A goiter is any visible enlargement of the thyroid gland. In the past, goiters were often due to a lack of iodine in the diet (iodized salt has greatly reduced such goiters). Goiters can be present in cases of either hormone overproduction (hyperthyroidism) or underproduction (hypothyroidism).

Image by TheVisualMD

Hormonal Control of the Menstrual Cycle, Animation.

Video by Alila Medical Media/YouTube

What Is High FSH?

Video by fertilityauthority/YouTube

What is FSH?

Video by fertilityauthority/YouTube

Human Physiology - Hormonal Regulation of Male Reproduction

Video by Janux/YouTube

What is Graves Disease?

Video by TriHealth Cincinnati/YouTube

Graves' Disease Education

Video by Jennifer Riccobono/YouTube

Reproductive System, Part 1 - Female Reproductive System: Crash Course A&P #40

Video by CrashCourse/YouTube

Male Sex Hormones

Video by Academic Algonquin/YouTube

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Normal Thyroid cell

A normal thyroid cell (Nthy.ori 3-1) adhered to gold surface. Picture taken by a Scanning electron microscope (SEM), University of Crete, Heraklion, Greece.

Image by ChronakiDimitra

Thyroid scintigraphy

5 different scintigramms taken from thyroids with different syndroms: A) normal thyroid, B) Graves disease, diffuse increased uptake in both thyroid lobes, C) Plummers disease (TMNG, toxic multinodular goitre), D) Toxic adenoma, E) Thyroiditis. Marker 99Tc

Image by Petros Perros

Thyroid Gland

TheVisualMD

Importance of Thyroid Gland

TheVisualMD

Thyroid Gland

CFCF

Follicular Cell of Thyroid Gland

TheVisualMD

Woman with visible Brain revealing Pituitary Gland

TheVisualMD

Follicle-stimulating hormone

MartaFF

Follicle-stimulating hormone

Mikael Haggstrom

hCG testing for pregnancy

Madprime

The classic finding of exophthalmos and lid retraction in Graves' disease

Jonathan Trobe, M.D. - University of Michigan Kellogg Eye Center

What are the symptoms of Graves' disease?

Original uploader was Madhero88 at en.wikipedia

What is Graves' ophthalmopathy?

Huy A Tran and Glenn EM Reeves

Thyroid Gland

TheVisualMD

Thyroid Stimulating Hormone

OpenStax College

Woman's neck region with visible thyroid

TheVisualMD

Woman with Visible Thyroid

TheVisualMD

Thyroid Stimulating Hormone (TSH)

TheVisualMD

Woman With Goiter Due to Hypothyroidism

TheVisualMD

3:15

Hormonal Control of the Menstrual Cycle, Animation.

Alila Medical Media/YouTube

1:16

What Is High FSH?

fertilityauthority/YouTube

2:46

What is FSH?

fertilityauthority/YouTube

3:38

Human Physiology - Hormonal Regulation of Male Reproduction

Janux/YouTube

2:25

What is Graves Disease?

TriHealth Cincinnati/YouTube

9:07

Graves' Disease Education

Jennifer Riccobono/YouTube

10:15

Reproductive System, Part 1 - Female Reproductive System: Crash Course A&P #40

CrashCourse/YouTube

2:30

Male Sex Hormones

Academic Algonquin/YouTube

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

Normal Thyroid cell

ChronakiDimitra

Thyroid scintigraphy

Petros Perros

Reverse Triiodothyronine Test

Reverse Triiodothyronine Test

Also called: Reverse T3, rT3

Reverse triiodothyronine (T3) is a biologically inactive thyroidal hormone that helps save energy in a stressful condition. Testing for rT3 allows doctors to assess the function of thyroidal gland if the symptoms of thyroidal disorder appear.

Reverse Triiodothyronine Test

Also called: Reverse T3, rT3

Reverse triiodothyronine (T3) is a biologically inactive thyroidal hormone that helps save energy in a stressful condition. Testing for rT3 allows doctors to assess the function of thyroidal gland if the symptoms of thyroidal disorder appear.

{"label":"Reverse T3 Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":10},"text":"Lower levels of rT3 indicate hypothyroidism (underactive thyroid).","conditions":["Hypothyroidism"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":10,"max":24},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":24,"max":50},"text":"Production of reverse T3 is typically triggered when the body is under significant stress, as in cases of serious or acute illness or injury.","conditions":["Hyperthyroidism","Serious injury","Prolonged stress","Extreme dieting","Liver or kidney disease","Chronic alcoholism","Insulin dependent diabetes"]}],"value":17}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
10
24
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
Normal range of rT3 is 10-24 ng/dL.
The levels of rT3 mayelevatedue to:
- hyperthyroidism (overactive thyroid)
- serious injury, surgery, burns
- prolonged stress periods
- extreme dieting
- starving
- liver or kidney disease
- chronic alcoholism
- exposure to chemicals and consuming medications
Lowerlevels of rT3 indicate hypothyroidism (underactive thyroid).
1. https://bostondirecthealth.com/primary-care-blog/thyroid-testing-why-you-should-check-your-t3-and-reverse-t3 [accessed on Apr 13, 2022]
2. https://www.endocrineweb.com/conditions/thyroid/what-reverse-t3 [accessed on Apr 13, 2022]
3. https://www.labcorp.com/tests/070104/reverse-t-sub-3-sub [accessed on Apr 13, 2022]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (7)

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

What Is Reverse T3?

Video by Holtorf Medical Group/YouTube

A Story About Hypothyroidism: Is this YOU?

Video by Hotze Health & Wellness Center/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Hyperthyroidism

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces hormones two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. Hyperthyroidism (when too much hormone is produced) is often caused by an autoimmune disorder called Graves' disease, in which antibodies produced by the immune system over-stimulate the thyroid.

Image by TheVisualMD

Woman's neck region with visible thyroid

TheVisualMD

Importance of Thyroid Gland

TheVisualMD

1:04

What Is Reverse T3?

Holtorf Medical Group/YouTube

6:18

A Story About Hypothyroidism: Is this YOU?

Hotze Health & Wellness Center/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

Hyperthyroidism

TheVisualMD

Triiodothyronine (T3) Tests

Triiodothyronine (T3) Tests

Also called: T3 Test, T3 Free and Total

This test measures triiodothyronine (T3) in your blood. Your thyroid gland makes T3. T3 plays an important role in the body's control of metabolism (the many processes that control the rate of activity in cells and tissues). The test is mainly used to diagnose hyperthyroidism.

Triiodothyronine (T3) Tests

Also called: T3 Test, T3 Free and Total

This test measures triiodothyronine (T3) in your blood. Your thyroid gland makes T3. T3 plays an important role in the body's control of metabolism (the many processes that control the rate of activity in cells and tissues). The test is mainly used to diagnose hyperthyroidism.

{"scale":"lin","step":0.1,"hideunits":false,"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":80},"text":"A lower-than-normal level of T3 may be a sign of a thyroid disorder."},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":80,"max":220},"text":"The total T3 test measures the T3 that is both attached to proteins and floating free in the blood. A normal result indicates normal thyroid function called euthyroid."},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":220,"max":300},"text":"A higher-than-normal level of T3 may be a sign of a thyroid disorder. A high level of T3 may occur in pregnancy (especially with morning sickness at the end of the first trimester) or with the use of birth control pills or estrogen."}],"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"disclaimer":"Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are \"within normal limits.\""}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
80
220
Your result is Low.
A lower-than-normal level of T3 may be a sign of a thyroid disorder.
Related conditions
{"scale":"lin","step":0.1,"hideunits":false,"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":2},"text":"A lower-than-normal level of T3 may be a sign of a thyroid disorder."},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":2,"max":4.4},"text":"The free T3 test measures the T3 that is floating free in the blood. The tests for free T3 are generally less accurate than for total T3."},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":4.4,"max":10},"text":"A higher-than-normal level of T3 may be a sign of a thyroid disorder. A high level of T3 may occur in pregnancy (especially with morning sickness at the end of the first trimester) or with the use of birth control pills or estrogen."}],"units":[{"printSymbol":"pg\/mL","code":"pg\/mL","name":"picogram per milliliter"}],"disclaimer":"Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are \"within normal limits.\""}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
pg/mL
2
4.4
Your result is Low.
A lower-than-normal level of T3 may be a sign of a thyroid disorder.
Related conditions
A triiodothyronine (T3) test measures the level of T3 in a sample of your blood. It's used to help diagnose thyroid disease.
Your thyroid is a small, butterfly-shaped gland at the base of your throat. It makes two hormones, T3 and T4 (thyroxine). Hormones are chemical messengers in your bloodstream that control the actions of certain cells or organs.
Thyroid hormones work together to control the way your body uses energy. They affect your weight, heart, body temperature, muscle strength, and even your mood. In children, thyroid hormones affect growth, too.
There are two forms of T3 in your blood:
- Free T3 is the active form that enters your tissues where it's needed.
- Bound T3 is attached to certain proteins which prevent it from entering your tissues. Most of your T3 is bound.
There are different tests for measuring T3:
- A total T3 test measures both bound and free T3 together. Medical experts think that this test is the more accurate way to measure T3.
- A free T3 test only measures free T3.
Other names: thyroid function test; total triiodothyronine, free triiodothyronine, FT3, TT3, radioimmunoassay FT3
A T3 test is used to help:
- Diagnose hyperthyroidism, a condition in which your thyroid gland makes too much thyroid hormone. The test can also help find out what's causing the condition.
- Diagnose pituitary disorders. The pituitary is a pea-sized gland at the base of your brain. It makes a hormone called TSH (thyroid stimulating hormone). TSH tells the thyroid how much T3 and T4 to make. So, abnormal T3 levels may be a sign of a pituitary problem.
- Monitor treatment for thyroid disease, including hyperthyroidism and hypothyroidism, which is when the thyroid gland makes to little thyroid hormone.
T3 tests are usually ordered with blood tests that measure T4 and TSH (thyroid stimulating hormone) tests.
You may need a T3 test if you have symptoms of hyperthyroidism (too much thyroid hormone). Symptoms may include:
- Anxiety, nervousness, irritability
- Weight loss, even though your appetite may increase
- Shaky hands, muscle weakness
- Sweating or being very sensitive to heat
- Irregular heartbeat (arrhythmia)
- Frequent bowel movements (poops)
- Goiter (an enlarged thyroid gland)
- Trouble sleeping and fatigue
You may also need a T3 test if:
- You take thyroid hormone medicine to treat a thyroid problem. A T3 test can check whether you're taking the right dose to keep your thyroid hormone levels in a healthy range.
- You had abnormal results on a TSH and/or T4 test. Providers usually order these tests first to look into a possible thyroid disorder. If your test results are abnormal or unclear, your provider may use a T3 test to confirm or rule out hyperthyroidism.
T3 testing isn't commonly used to help check for hypothyroidism (too little thyroid hormone). That's because other thyroid tests can diagnose hypothyroidism earlier than a T3 test.
To understand the results of your T3 test, your provider will usually compare them with the results of your TSH and T4 tests. Like T3, T4 tests may measure either free or total T4, but providers usually measure free T4.
Your provider will look for different combinations of high, low, and normal results. Each combination suggests a different thyroid condition. Ask your provider to explain what your test results say about your health.
In general:
- Normal T3 levels (free or total) alone do not rule out thyroid disease. But if your TSH and free T4 levels are also normal, you probably don't have a thyroid condition.
- High T3 levels (free or total) may mean you have hyperthyroidism (too much thyroid hormone).
  
  High T3 levels with:
  Low TSH and high free T4 levels may mean that a problem with your thyroid gland is causing too much thyroid hormone.
  Normal or high TSH and high free T4 levels may mean that a pituitary gland condition is causing too much thyroid hormone.
- Low T3 levels (free or total) may mean hypothyroidism (too little thyroid hormone).
  
  Low or normal T3 levels with:
  High TSH levels and low free T4 levels may mean that a problem with your thyroid gland is causing too little thyroid hormone.
  Low TSH and low free T4 levels may mean that a pituitary gland condition is causing too little thyroid hormone.
If you have questions about your results, talk with your provider.
1. Triiodothyronine (T3) Tests: MedlinePlus Medical Test [accessed on Jan 16, 2024]
2. T3 test: MedlinePlus Medical Encyclopedia [accessed on Jan 16, 2024]
3. T3 Test - Testing.com. Nov 29, 2022 [accessed on Jan 16, 2024]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (9)

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which play key roles in regulating many aspects of metabolism, the rate at which the cells use energy and carry out chemical processes. The thyroid and the hormones it produces are under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland.

Image by TheVisualMD

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

How does the thyroid manage your metabolism? - Emma Bryce

Video by TED-Ed/YouTube

T3 And T4, What Do They Do?

Video by EmpowHER/YouTube

Understanding Thyroid Function Tests

Video by AdonaiDEC/YouTube

Thyroid Blood Tests

Video by Tom Wade MD/YouTube

Understanding Blood Test Video 2: Comprehensive Metabolic Panel

Video by Health in a Nutshell/YouTube

Thyroid Gland

TheVisualMD

Woman's neck region with visible thyroid

TheVisualMD

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

3:37

How does the thyroid manage your metabolism? - Emma Bryce

TED-Ed/YouTube

1:56

T3 And T4, What Do They Do?

EmpowHER/YouTube

6:07

Understanding Thyroid Function Tests

AdonaiDEC/YouTube

6:57

Thyroid Blood Tests

Tom Wade MD/YouTube

5:17

Understanding Blood Test Video 2: Comprehensive Metabolic Panel

Health in a Nutshell/YouTube

Triiodothyronine Uptake Test

Triiodothyronine Uptake Test

Also called: T3 Uptake, T3U, T3 Resin Uptake, T3RU, Thyroid Hormone-binding Ratio, THBR

₃ uptake test is an indirect way of evaluating the levels of thyroxine-related protein and thyroid hormones. This test is used together with other thyroid tests to assess the function of your thyroid gland in case of suspected disorder.

Triiodothyronine Uptake Test

Also called: T3 Uptake, T3U, T3 Resin Uptake, T3RU, Thyroid Hormone-binding Ratio, THBR

₃ uptake test is an indirect way of evaluating the levels of thyroxine-related protein and thyroid hormones. This test is used together with other thyroid tests to assess the function of your thyroid gland in case of suspected disorder.

{"label":"Triiodothyronine Uptake Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"%","code":"%","name":"percent"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":24},"text":"You have low T<sub>3<\/sub> uptake results. Talk to your doctor to know what this means in your specific case. ","conditions":["Hypothyroidism","Pregnancy","Estrogen therapy","Liver failure",""]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":24,"max":39},"text":"Normal results may slightly vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":39,"max":100},"text":"You have increased T<sub>3<\/sub> uptake results. Talk to your doctor to know what this means in your specific case. ","conditions":["Hyperthyroidism","Kidney damage","Genetic disorders"]}],"value":31.5}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
%
24
39
Your result is Normal.
Normal results may slightly vary based on the laboratory and the method used.
Related conditions
Your doctor may consider ordering a T₃ uptake test if you have signs or symptoms related to a thyroid disorder. These include:
- Fatigue
- Persistent irritation
- Unexplained weight changes
- Headaches
- Difficulty focusing
- Family history of thyroid disease
1. T3RU test: MedlinePlus Medical Encyclopedia [accessed on Oct 05, 2018]
2. Thyroid Function Tests - Clinical Methods - NCBI Bookshelf [accessed on Oct 05, 2018]
3. 001156: T3 Uptake | LabCorp [accessed on Oct 05, 2018]
4. Understanding the T3 Uptake Blood Test Results - HRF [accessed on Oct 05, 2018]
5. Blood Test: T3 Resin Uptake (T3RU) (for Parents) [accessed on Oct 05, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (6)

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Thyroxine 3D Molecule

The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. (MESH/NLM/NIH)

Endocrine System

The endocrine system is comprised of specialized glands throughout the body that use produce hormones that regulate a wide range of metabolic processes, the rate at which cells use energy and carry out chemical processes. The pea-sized pituitary gland is often referred to as the \"master gland\" because it regulates the activities of other endocrine glands, but the pituitary gland, in turn, takes its orders from the brain's hypothalamus. The thyroid gland is the regulator of metabolism of the human body. It produces 2 hormones, tri-iodothyronine (T3) and tetra-iodothyronine (T4), which regulate basal metabolic rate and blood calcium levels respectively. The thyroid works in conjunction with the parathyroids which are embedded on the posterior aspect of the gland. The four small parathyroid glands produce calcitonin which lowers blood calcium levels by inhibiting the rate of decalcification. The thyroid receives instructions to produce and release its hormones from the pituitary gland which sits in a small depression in the cranial floor. The parathyroid secrets its product when it senses an increase of calcium levels in the blood stream.

Image by TheVisualMD

Thyroid Blood Tests

Video by Tom Wade MD/YouTube

Understanding Thyroid Function Tests

Video by AdonaiDEC/YouTube

Thyroid Gland, Hormones and Thyroid Problems, Animation

Video by Alila Medical Media/YouTube

Woman's neck region with visible thyroid

TheVisualMD

Thyroxine 3D Molecule

Endocrine System

TheVisualMD

6:57

Thyroid Blood Tests

Tom Wade MD/YouTube

6:07

Understanding Thyroid Function Tests

AdonaiDEC/YouTube

4:03

Thyroid Gland, Hormones and Thyroid Problems, Animation

Alila Medical Media/YouTube

Thyroxine Test

Thyroxine Test

Also called: T₄, total T₄ concentration, Thyroxine screen, Tetraiodothyronine

A thyroxine test measures the level of thyroxine (T₄) in the blood. Too much or too little T₄ can indicate thyroid disease.

Thyroxine Test

Also called: T₄, total T₄ concentration, Thyroxine screen, Tetraiodothyronine

A thyroxine test measures the level of thyroxine (T₄) in the blood. Too much or too little T₄ can indicate thyroid disease.

{"label":"Thyroxine Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"\u03bcg\/dL","code":"ug\/dL","name":"microgram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":4.5},"text":"Low levels of T4 may indicate an underactive thyroid, also known as hypothyroidism.","conditions":["Hypothyroidism","Hashimoto's disease","Chronic thyroiditis","Myxedema"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":4.5,"max":12},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":12,"max":100},"text":"High levels of T4 may indicate an overactive thyroid, also known as hyperthyroidism.","conditions":["Hyperthyroidism","Graves' disease","Acute thyroiditis"]}],"value":8.3}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
μg/dL
4.5
12
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
{"label":"Thyroxine, Free Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":0.82},"text":"If the thyroid gland produces too little T4, the result is hypothyroidism (underactive thyroid gland).<br \/>\n","conditions":["Hypothyroidism","Hashimoto's Disease",""]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0.82,"max":1.77},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":1.77,"max":5},"text":"If the thyroid gland produces too much T4, the result is hyperthyroidism (overactive thyroid gland)","conditions":["Hyperthyroidism","Grave's Disease"]}],"value":1.3}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
0.82
1.77
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
A thyroxine test helps diagnose disorders of the thyroid. The thyroid is a small, butterfly-shaped gland located near the throat. Your thyroid makes hormones that regulate the way your body uses energy. It also plays an important role in regulating your weight, body temperature, muscle strength, and even your mood. Thyroxine, also known as T₄, is a type of thyroid hormone. This test measures the level of T₄ in your blood. Too much or too little T₄ can indicate thyroid disease.
The T₄ hormone comes in two forms:
- Free T₄, which enters the body tissues where it's needed
- Bound T₄, which attaches to proteins, preventing it from entering body tissues
A test that measures both free and bound T₄ is called a total T₄ test. Other tests measure just free T₄. A free T₄ test is considered more accurate than a total T₄ test for checking thyroid function.
Thyroid disease is much more common in women and most often occurs under the age of 40. It also tend to run in families. You may need a thyroxine test if a family member has ever had thyroid disease or if you have symptoms of having too much thyroid hormone in your blood, a condition called hyperthyroidism, or symptoms of having too little thyroid hormone, a condition called hypothyroidism.
Symptoms of hyperthyroidism, also known as overactive thyroid, include:
- Anxiety
- Weight loss
- Tremors in the hands
- Increased heart rate
- Puffiness
- Bulging of the eyes
- Trouble sleeping
Symptoms of hypothyroidism, also known as underactive thyroid, include:
- Weight gain
- Fatigue
- Hair loss
- Low tolerance for cold temperatures
- Irregular menstrual periods
- Constipation
Your results may come in the form of total T₄, free T₄, or a free T₄ index.
- The free T₄ index includes a formula that compares free and bound T₄.
- High levels of any of these tests (total T₄, free T₄, or free T₄ index) may indicate an overactive thyroid, also known as hyperthyroidism.
- Low levels of any of these tests (total T₄, free T₄, or free T₄ index) may indicate an underactive thyroid, also known as hypothyroidism.
If your T₄ test results are not normal, your health care provider will likely order more thyroid tests to help make a diagnosis. These may include:
- T₃ thyroid hormone tests. T₃ is another hormone made by the thyroid.
- A TSH (thyroid stimulating hormone) test. TSH is a hormone made by the pituitary gland. It stimulates the thyroid to produce T₄ and T₃ hormones.
- Tests to diagnose Graves' disease, an autoimmune disease that causes hyperthyroidism
- Tests to diagnose Hashimoto's thyroiditis, an autoimmune disease that causes hypothyroidism
1. Thyroxine (T4) Test: MedlinePlus Lab Test Information [accessed on Oct 03, 2018]
2. 000620: Thyroid Profile With TSH | LabCorp [accessed on Oct 03, 2018]
3. T4 - Clinical: T4 (Thyroxine), Total Only, Serum [accessed on Oct 03, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (15)

Thyroxine, Total (T4): Thyroid Gland

The thyroid is a 2-inch, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The gland consists of two lobes, which lie on either side of the windpipe. The thyroid produces the hormones thyroxine (T4) and triiodothyronine (T3), which help maintain body temperature, heart rate, and metabolism rates.

Image by TheVisualMD

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Thyroxine, Total (T4): Pituitary Gland

The pituitary is a pea-size gland attached to the base of the brain. It is often referred to as the \"master gland\" because it regulates the activities of other endocrine glands. The pituitary, however, takes its orders from the hypothalamus, an area of the brain that sits above the pituitary and is connected to it by neurons. The hypothalamus decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Woman With Goiter Due to Hypothyroidism

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. A goiter is any visible enlargement of the thyroid gland. In the past, goiters were often due to a lack of iodine in the diet (iodized salt has greatly reduced such goiters). Goiters can be present in cases of either hormone overproduction (hyperthyroidism) or underproduction (hypothyroidism).

Image by TheVisualMD

Thyroxine 3D Molecule

The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. (MESH/NLM/NIH)

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Thyroid Animation

Video by Columbia University Department of Surgery/YouTube

Thyroid Gland, Hormones and Thyroid Problems, Animation

Video by Alila Medical Media/YouTube

Thyroid Gland - Thyroid Hormones

Video by Armando Hasudungan/YouTube

How does the thyroid manage your metabolism? - Emma Bryce

Video by TED-Ed/YouTube

Understanding Thyroid Function Tests

Video by AdonaiDEC/YouTube

T3 And T4, What Do They Do?

Video by EmpowHER/YouTube

Woman's neck region with visible thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck. The gland produces two main hormones, thyroxine and triiodothyronine. The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid is under the control of a hormone called thyroid-stimulating hormone produced by the pituitary gland; the pituitary gland, in turn, takes its orders from the hypothalamus. Thyroid problems usually fall into one of two categories: hypothroidism, when the gland produces too little hormone; or hyperthroidism, when the gland produces too much.

Image by TheVisualMD

Thyroxine

The structural formula (left) and a space-filling model (right) of (S)-triiodothyronine (T3, also called liothyronine in the pharmaceutical industry)

Image by Benjah-bmm27

Thyroxine, Total (T4): Thyroid Gland

TheVisualMD

Importance of Thyroid Gland

TheVisualMD

Thyroxine, Total (T4): Pituitary Gland

TheVisualMD

Woman With Goiter Due to Hypothyroidism

TheVisualMD

Thyroxine 3D Molecule

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

1:48

Thyroid Animation

Columbia University Department of Surgery/YouTube

4:03

Thyroid Gland, Hormones and Thyroid Problems, Animation

Alila Medical Media/YouTube

12:47

Thyroid Gland - Thyroid Hormones

Armando Hasudungan/YouTube

3:37

How does the thyroid manage your metabolism? - Emma Bryce

TED-Ed/YouTube

6:07

Understanding Thyroid Function Tests

AdonaiDEC/YouTube

1:56

T3 And T4, What Do They Do?

EmpowHER/YouTube

Woman's neck region with visible thyroid

TheVisualMD

Thyroxine

Benjah-bmm27

Thyroxine, Free Test

Thyroxine, Free Test

Also called: Free thyroxine, Free T4, FT4, free T4 concentration

A thyroxine test measures the level of thyroxine (T₄) in the blood. Too much or too little T₄ can indicate thyroid disease.

Thyroxine, Free Test

Also called: Free thyroxine, Free T4, FT4, free T4 concentration

A thyroxine test measures the level of thyroxine (T₄) in the blood. Too much or too little T₄ can indicate thyroid disease.

{"label":"Thyroxine, Free Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/dL","code":"ng\/dL","name":"nanogram per deciliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":0.82},"text":"If the thyroid gland produces too little T4, the result is hypothyroidism (underactive thyroid gland).<br \/>\n","conditions":["Hypothyroidism","Hashimoto's Disease",""]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0.82,"max":1.77},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":1.77,"max":5},"text":"If the thyroid gland produces too much T4, the result is hyperthyroidism (overactive thyroid gland)","conditions":["Hyperthyroidism","Grave's Disease"]}],"value":1.3}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/dL
0.82
1.77
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
{"label":"Free Thyroxine Index Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"arb. U","code":"[arb'U]","name":"arbitary unit"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":1.2},"text":"Low levels of any of the thyroxine tests may indicate an underactive thyroid, also known as hypothyroidism.","conditions":[]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":1.2,"max":4.9},"text":"The free T<sub>4<\/sub> index includes a formula that compares free and bound T<sub>4<\/sub>.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":4.9,"max":10},"text":"High levels of any of the thyroxine tests may indicate an overactive thyroid, also known as hyperthyroidism.","conditions":[]}],"value":3.1}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
arb. U
1.2
4.9
Your result is Normal.
₄ index includes a formula that compares free and bound T₄.
Related conditions
A thyroxine test helps diagnose disorders of the thyroid. The thyroid is a small, butterfly-shaped gland located near the throat. Your thyroid makes hormones that regulate the way your body uses energy. It also plays an important role in regulating your weight, body temperature, muscle strength, and even your mood. Thyroxine, also known as T₄, is a type of thyroid hormone. This test measures the level of T₄ in your blood. Too much or too little T₄ can indicate thyroid disease.
The T₄ hormone comes in two forms:
- Free T₄, which enters the body tissues where it's needed
- Bound T₄, which attaches to proteins, preventing it from entering body tissues
A test that measures both free and bound T₄ is called a total T₄ test. Other tests measure just free T₄. A free T₄ test is considered more accurate than a total T₄ test for checking thyroid function.
Thyroid disease is much more common in women and most often occurs under the age of 40. It also tend to run in families. You may need a thyroxine test if a family member has ever had thyroid disease or if you have symptoms of having too much thyroid hormone in your blood, a condition called hyperthyroidism, or symptoms of having too little thyroid hormone, a condition called hypothyroidism.
Symptoms of hyperthyroidism, also known as overactive thyroid, include:
- Anxiety
- Weight loss
- Tremors in the hands
- Increased heart rate
- Puffiness
- Bulging of the eyes
- Trouble sleeping
Symptoms of hypothyroidism, also known as underactive thyroid, include:
- Weight gain
- Fatigue
- Hair loss
- Low tolerance for cold temperatures
- Irregular menstrual periods
- Constipation
Your results may come in the form of total T₄, free T₄, or a free T₄ index.
- The free T₄ index includes a formula that compares free and bound T₄.
- High levels of any of these tests (total T₄, free T₄, or free T₄ index) may indicate an overactive thyroid, also known as hyperthyroidism.
- Low levels of any of these tests (total T₄, free T₄, or free T₄ index) may indicate an underactive thyroid, also known as hypothyroidism.
If your T₄ test results are not normal, your health care provider will likely order more thyroid tests to help make a diagnosis. These may include:
- T₃ thyroid hormone tests. T₃ is another hormone made by the thyroid.
- A TSH (thyroid stimulating hormone) test. TSH is a hormone made by the pituitary gland. It stimulates the thyroid to produce T₄ and T₃ hormones.
- Tests to diagnose Graves' disease, an autoimmune disease that causes hyperthyroidism
- Tests to diagnose Hashimoto's thyroiditis, an autoimmune disease that causes hypothyroidism
1. 001974: Thyroxine (T4), Free, Direct | LabCorp [accessed on Oct 03, 2018]
2. Free T4 [accessed on Oct 03, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (13)

Follicular Cell of Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3). The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid contains spherical follicles that absorb iodine ions from the blood for use in the production of T4 and T3. Iodine deficiency, rare in the U.S., affects two billion people worldwide and is the leading preventable cause of mental retardation.

Image by TheVisualMD

Thyroid Gland

Illustration of the Thyroid Gland

Image by OpenStax College

Microsomal Thyroid Antibody

Microsomes are tiny structures found inside cells of the thyroid gland, which produce hormones that regulate our metabolism. When thyroid cells are damaged, the body responds by producing antibodies against the microsomes. The presence of these antibodies in the blood helps diagnose a variety of thyroid disorders.

Image by TheVisualMD

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Pituitary gland

Diagram of pituitary and pineal glands in the human brain

Image by Images are generated by Life Science Databases(LSDB)

Thyroxine 3D Molecule

The major hormone derived from the thyroid gland. Thyroxine is synthesized via the iodination of tyrosines (MONOIODOTYROSINE) and the coupling of iodotyrosines (DIIODOTYROSINE) in the THYROGLOBULIN. Thyroxine is released from thyroglobulin by proteolysis and secreted into the blood. Thyroxine is peripherally deiodinated to form TRIIODOTHYRONINE which exerts a broad spectrum of stimulatory effects on cell metabolism. (MESH/NLM/NIH)

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

How does the thyroid manage your metabolism? - Emma Bryce

Video by TED-Ed/YouTube

T3 And T4, What Do They Do?

Video by EmpowHER/YouTube

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

Thyroid Gland - Thyroid Hormones

Video by Armando Hasudungan/YouTube

Thyroid Animation

Video by Columbia University Department of Surgery/YouTube

Follicular Cell of Thyroid Gland

TheVisualMD

Thyroid Gland

OpenStax College

Microsomal Thyroid Antibody

TheVisualMD

Importance of Thyroid Gland

TheVisualMD

Pituitary gland

Images are generated by Life Science Databases(LSDB)

Thyroxine 3D Molecule

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

3:37

How does the thyroid manage your metabolism? - Emma Bryce

TED-Ed/YouTube

1:56

T3 And T4, What Do They Do?

EmpowHER/YouTube

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

12:47

Thyroid Gland - Thyroid Hormones

Armando Hasudungan/YouTube

1:48

Thyroid Animation

Columbia University Department of Surgery/YouTube

Thyroxine-Binding Globulin Test

Thyroxine-Binding Globulin Test

Also called: TBG

This test measures the amount of thyroxine-binding globulin (TBG) in a sample of your blood. It is used to assess thyroid gland function and to help diagnose thyroid disorders.

Thyroxine-Binding Globulin Test

Also called: TBG

This test measures the amount of thyroxine-binding globulin (TBG) in a sample of your blood. It is used to assess thyroid gland function and to help diagnose thyroid disorders.

{"label":"Thyroxine-Binding Globulin Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"\u03bcg\/mL","code":"ug\/mL","name":"microgram per milliliter"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":13},"text":"Your TBG results are low. Talk to your doctor to know what this means in your specific case. ","conditions":["Acute body illness","Hyperthyroidism","Malnutrition","Nephrotic syndrome","Acromegaly"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":13,"max":39},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":39,"max":100},"text":"Your TBG results are high. Talk to your doctor to know what this means in your specific case. Note: TBG levels are normally increased during pregnancy and in newborns.","conditions":["Pregnancy","Liver disease","Acute intermittent porphyria","Hypothyroidism"]}],"value":26}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
μg/mL
13
39
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
Your doctor may order this test if you have signs and symptoms like:
- Weight changes
- Hair loss
- Constipation
- Anxiety
- Rapid heartbeats
- Tremors in hands
- Diarrhea
- Fatigue
- Eye and skin dryness
Normal range is 13 to 39 micrograms per deciliter (µg/dL), or 150 to 360 nanomoles per liter (nmol/L).
TBG levels are normally elevated during pregnancy and in newborns. Use of certain medications can also affect TBG blood levels.
Higher values than the normal range besides the conditions mentioned above can be due to:
- Liver disease
- A rare genetic disorder called acute intermittent porphyria
- Hypothyroidism
Low values than the normal range are indicative of:
- Acute body illness
- Hyperthyroidism
- Malnutrition
- Nephrotic syndrome
- Acromegaly
1. TBG blood test: MedlinePlus Medical Encyclopedia [accessed on Oct 05, 2018]
2. High serum thyroxine-binding globulin--an important cause of hyperthyroxinaemia. [accessed on Oct 05, 2018]
3. Serum TBG (Thyroxine-Binding Globulin) Level Test [accessed on Oct 05, 2018]
4. 001735: Thyroxine-binding Globulin (TBG), Serum | LabCorp [accessed on Oct 05, 2018]
5. TBGI - Clinical: Thyroxine-Binding Globulin (TBG), Serum [accessed on Oct 05, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (1)

Thyroid Gland

National Cancer Institute / Don Bliss (Illustrator)

Thyroid Peroxidase Antibody Test

Thyroid Peroxidase Antibody Test

Also called: TPO Ab, Thyroperoxidase Ab, Antimicrosomal Antibody, Antithyroid Microsomal Antibody, Anti-TPO antibody

Thyroid peroxidase (TPO) antibodies are proteins that mistakenly attack the thyroid gland, potentially leading to damage, long-term inflammation (thyroiditis), and disruption of thyroid function.

Thyroid Peroxidase Antibody Test

Also called: TPO Ab, Thyroperoxidase Ab, Antimicrosomal Antibody, Antithyroid Microsomal Antibody, Anti-TPO antibody

Thyroid peroxidase (TPO) antibodies are proteins that mistakenly attack the thyroid gland, potentially leading to damage, long-term inflammation (thyroiditis), and disruption of thyroid function.

{"label":"Thyroid Peroxidase Antibody Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"(i.U.)\/mL","code":"[IU]\/mL","name":"international unit per milliliter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":34},"text":"Normal value ranges may vary depending on your age, gender, health history, the method used for the test, among other things.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":34,"max":200},"text":"An abnormal result does not necessarily mean that you have a thyroid condition, but, rather, that you have an increased risk of developing thyroid disease in the future.","conditions":["Granulomatous thyroiditis","Hashimoto's thyroiditis","Graves\u2019 disease","Rheumatoid arthritis","Systemic lupus erythematosus","Sjogren syndrome"]}],"value":17}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
(i.U.)/mL
34
Your result is Normal.
Normal value ranges may vary depending on your age, gender, health history, the method used for the test, among other things.
Related conditions
Your doctor may want to order this test to guide treatment or to help diagnose conditions or diseases that affect the thyroid gland, such as:
- Hashimoto thyroiditis.
- Graves disease.
This test can also be used to help differentiate autoimmune thyroid disorders from nonautoimmune disorders, such as hypothyroidism (underactive thyroid).
Normal value ranges may vary depending on your age, gender, health history, the method used for the test, among other things.
Higher-than-normal levels may be due to:
- Hashimoto thyroiditis
- Graves' disease
- Granulomatous thyroiditis
- Other autoimmune disorders, such as rheumatoid arthritis, Sjögren syndrome, or systemic lupus erythematosus, among others.
An abnormal result does not necessarily mean that you have a thyroid condition, but, rather, that you have an increased risk of developing thyroid disease in the future.
1. Antithyroid microsomal antibody: MedlinePlus Medical Encyclopedia [accessed on Oct 05, 2018]
2. Thyroid Antibodies [accessed on Oct 05, 2018]
3. 006676: Thyroid Peroxidase (TPO) Antibodies | LabCorp [accessed on Oct 05, 2018]
4. TAB - Clinical: Thyroid Autoantibodies Profile, Serum [accessed on Oct 05, 2018]
5. TPO - Clinical: Thyroperoxidase (TPO) Antibodies, Serum [accessed on Oct 05, 2018]
6. Thyroid Autoantibodies Test [accessed on Oct 05, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Thyroglobulin Test

Thyroglobulin Test

Also called: TGB, Thyroglobulin Tumor Marker

A thyroglobulin test measures the level of thyroglobulin in your blood. Thyroglobulin is a protein made by your thyroid. The test is mostly used to find out if thyroid cancer treatment has worked.

Thyroglobulin Test

Also called: TGB, Thyroglobulin Tumor Marker

A thyroglobulin test measures the level of thyroglobulin in your blood. Thyroglobulin is a protein made by your thyroid. The test is mostly used to find out if thyroid cancer treatment has worked.

{"label":"Thyroglobulin Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"ng\/mL","code":"ng\/mL","name":"nanogram per milliliter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":33},"text":"Normal results vary based on the laboratory and the method used.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":33,"max":200},"text":"Higher values than the normal range can be due to the presence of thyroid cancer. ","conditions":["Thyroid carcinoma","Goiter","Hyperthyroidism","Graves' disease","Thyroiditis"]}],"value":16.5}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/mL
33
Your result is Normal.
Normal results vary based on the laboratory and the method used.
Related conditions
A thyroglobulin test is mostly used to:
- See if thyroid cancer treatment was successful and guide decisions about more treatment.
- Predict how your cancer will behave over time.
- See if cancer has returned after successful treatment.
Thyroglobulin tests may also be used to help diagnose hyperthyroidism and hypothyroidism, which are common thyroid conditions that aren't cancer.
Understanding the results of a thyroglobulin test after treatment can be complicated. The meaning of your results depends on your health history, the type of treatment you had, and the results of other tests. So, it's best to ask your provider to explain what your test results say about your health.
In general, if you were tested after treatment for thyroid cancer:
- Very low levels or no thyroglobulin may mean that your cancer treatment has worked to get rid of all thyroid tissue, including cancer. But you will still need more testing over time to make sure.
- Thyroglobulin levels that stay high or increase may mean that:
  Your treatment did not get rid of all thyroid tissue in your body.
  You still have thyroid cancer in your body that has grown and may have spread.
- Thyroglobulin levels that were low after treatment but later increased may mean that your thyroid cancer has come back after treatment.
1. Thyroglobulin: MedlinePlus Lab Test Information [accessed on Dec 14, 2022]
2. Lab Tests Online: Thyroglobulin [accessed on Oct 03, 2018]
3. Giovanella L et al, Unstimulated high-sensitive thyroglobulin in follow-up of differentiated thyroid cancer patients: a meta-analysis. J Clin Endocrinol Metab. 2013 Nov 27. [accessed on Oct 03, 2018]
4. Thyroid tests. The American Association of Endocrine Surgeons (AAES). [accessed on Oct 03, 2018]
5. Thyroglobulin (Tg) and Tg Antibody (TgAb) Testing for Patients Treated for Thyroid Cancers. By Carole Spencer, Ph.D., F.A.C.B President, 2001-2002, American Thyroid Association. [accessed on Oct 03, 2018]
6. Pellegriti, G. , Scollo, C. , Regalbuto, . C., Attard, M. , Marozzi, P. , Vermiglio, F. , Violi, M. A., Cianci, M. , Vigneri, R. , Pezzino, . V. and Squatrito, S. (2003), The diagnostic use of the rhTSH/thyroglobulin test in differentiated thyroid cancer patients with persistent disease and low thyroglobulin levels. Clinical Endocrinology, 58: 556-561. doi:10.1046/j.1365-2265.2003.01744.x [accessed on Oct 03, 2018]
7. Indrasena BSH. Use of thyroglobulin as a tumour marker. World Journal of Biological Chemistry. 2017;8(1):81-85. doi:10.4331/wjbc.v8.i1.81. [accessed on Oct 03, 2018]
8. Medscape: Thyroglobulin (Tg) Measurement [accessed on Oct 03, 2018]
9. Mayo Clinic: Thyroglobulin, Tumor Marker, Serum [accessed on Oct 03, 2018]
10. LabCorp: Thyroglobulin, Comprehensive (With Anti-Tg Screen and Reflex to RIA) (Endocrine Sciences) [accessed on Oct 03, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (6)

A hormone called TSH, produced by the pituitary gland, controls the thyroid and the hormones it produces.

The thyroid is a 2-inch, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid produces two main hormones, thyroxine (T4) and triiodothyronine (T3), which play key roles in regulating many aspects of metabolism--the rate at which the cells use energy and carry out chemical processes. A hormone called TSH, produced by the pituitary gland, controls the thyroid and the hormones it produces.

Image by TheVisualMD

Thyroglobulin (Tg): Thyroid Cancer

There may be no symptoms of thyroid cancer. If there are symptoms, they can include enlarged lymph nodes in the neck, problems with swallowing, hoarseness or changes in the voice, discomfort in the neck, and a chronic cough. Papillary thyroid cancer (about 80% of all cases) usually grows slowly and may spread to the lymph nodes in the neck. Follicular thyroid cancer (about 15% of cases) also tends to spread slowly, typically to the lungs. Thyroid cancer is treated through surgical removal of all or most of the thyroid, and possibly lymph nodes in the neck as well. Radioactive iodine treatment may be used after surgery. The prognosis for people with thyroid cancer is good: 90% of patients with papillary thyroid cancer and 80% of follicular thyroid cancer patients are alive 10 years after diagnosis.

Image by TheVisualMD

Thyroxine

The structural formula (left) and a space-filling model (right) of (S)-triiodothyronine (T3, also called liothyronine in the pharmaceutical industry)

Image by Benjah-bmm27

Regulation of Body Processes

ADH and aldosterone increase blood pressure and volume. Angiotensin II stimulates release of these hormones. Angiotensin II, in turn, is formed when renin cleaves angiotensinogen. (credit: modification of work by Mikael Häggström)

Image by CNX Openstax (credit: modification of work by Mikael Häggström)

Hashimoto's Disease (Thyroiditis)

Video by UW Health/YouTube

Hashimoto's Thyroiditis Treatment Options

Video by drcheimlich/YouTube

A hormone called TSH, produced by the pituitary gland, controls the thyroid and the hormones it produces.

TheVisualMD

Thyroglobulin (Tg): Thyroid Cancer

TheVisualMD

Thyroxine

Benjah-bmm27

Regulation of Body Processes

CNX Openstax (credit: modification of work by Mikael Häggström)

0:52

Hashimoto's Disease (Thyroiditis)

UW Health/YouTube

5:01

Hashimoto's Thyroiditis Treatment Options

drcheimlich/YouTube

Thyroglobulin Antibody Test

Thyroglobulin Antibody Test

Also called: Antithyroglobulin Antibody, TGAb

Thyroglobulin is a protein that helps control metabolic functions and production of hormones T3 and T4 in the thyroid gland. Thyroglobulin antibodies are proteins that mistakenly attack the gland, potentially leading to damage, long-term inflammation (thyroiditis) and disruption of thyroid function.

Thyroglobulin Antibody Test

Also called: Antithyroglobulin Antibody, TGAb

Thyroglobulin is a protein that helps control metabolic functions and production of hormones T3 and T4 in the thyroid gland. Thyroglobulin antibodies are proteins that mistakenly attack the gland, potentially leading to damage, long-term inflammation (thyroiditis) and disruption of thyroid function.

{"label":"Thyroglobulin Antibody Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"(i.U.)\/mL","code":"[IU]\/mL","name":"international unit per milliliter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":4},"text":"Normal reference ranges can vary from laboratory to laboratory.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":4,"max":10},"text":"A positive result means that elevated amounts of antithyroglobulin antibodies were found in your blood. ","conditions":["Disseminated thyroid carcinoma","Autoimmune hypothyroidism","Hyperthyroidism","Graves\u2019 disease","Hashimoto thyroiditis","Subacute thyroiditis","Underactive thyroid","Systemic lupus erythematosus","Type 1 diabetes","Pregnancy"]}],"value":2}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
(i.U.)/mL
4
Your result is Normal.
Normal reference ranges can vary from laboratory to laboratory.
Related conditions
Your doctor may want to order this test to monitor treatment or to help diagnose conditions or diseases that affect the thyroid gland, such as:
- Autoimmune thyroiditis
- Hashimoto thyroiditis
- Endemic goiter
- Recurrence of thyroid cancer
The normal reference range for thyroglobulin antibodies is less than 4.0 IU/mL.
A positive result means antithyroglobulin antibodies were found in your blood. This can happen as a result of:
- Disseminated thyroid carcinoma
- Autoimmune hypothyroidism
- Hyperthyroidism
- Graves’ disease
- Hashimoto thyroiditis
- Subacute thyroiditis
- Underactive thyroid
- Systemic lupus erythematosus
- Type 1 diabetes
- Pregnancy
1. 006685: Thyroglobulin Antibody | LabCorp [accessed on Oct 03, 2018]
2. Antithyroglobulin antibody test: MedlinePlus Medical Encyclopedia [accessed on Oct 03, 2018]
3. TGAB - Clinical: Thyroglobulin Antibody, Serum [accessed on Oct 03, 2018]
4. Thyroglobulin [accessed on Oct 03, 2018]
5. Thyroid Antibodies [accessed on Oct 03, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (13)

OWH Graves’ Disease Factsheet

Document by Office on Women's Health, U.S. Department of Health and Human Services

Document by Office on Women's Health, U.S. Department of Health and Human Services

Woman with Visible Thyroid

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam's apple. The thyroid gland produces two main hormones, thyroxine (T4) and triiodothyronine (T3). The hormones help maintain body temperature, heart rate, moods, energy levels, bowel function and rates of fat, protein and carbohydrate metabolism. The thyroid and the hormones it produces are under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland, which is often referred to as the \"master gland\" because it regulates the activities of other endocrine glands.

Image by TheVisualMD

Thyroid-stimulating Hormone: Thyroid

The thyroid gland produces the hormones thyroxine (T4) and triiodothyronine (T3), which help maintain body temperature, heart rate, moods, and metabolism rates. Levels of T4 and T3 are controlled by TSH (thyroid-stimulating hormone), which is produced by the pituitary gland.

Image by TheVisualMD

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam`s apple. Hormones produced by the thyroid gland have an enormous impact on many aspects of metabolism.

Image by TheVisualMD

Thyroid Gland

The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Image by CNX Openstax

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

The thyroid gland’s production of thyroid hormones (T3 and T4) is regulated by thyroid-stimulating hormone (TSH), which is made by the pituitary gland.

Image by NIDDK Image Library

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Endocrine Glands

The pituitary gland is located at (a) the base of the brain and (b) connected to the hypothalamus by the pituitary stalk. (credit a: modification of work by NCI; credit b: modification of work by Gray’s Anatomy)

Image by CNX Openstax

Thyroid problems - most common thyroid problems, symptoms and treatment

Video by Healthchanneltv / cherishyourhealthtv/YouTube

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

What Is A Thyroid Nodule?

Video by Swedish/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

OWH Graves’ Disease Factsheet

Office on Women's Health, U.S. Department of Health and Human Services

Office on Women's Health, U.S. Department of Health and Human Services

Woman with Visible Thyroid

TheVisualMD

Thyroid-stimulating Hormone: Thyroid

TheVisualMD

Thyroid Gland

TheVisualMD

Thyroid Gland

CNX Openstax

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

NIDDK Image Library

Importance of Thyroid Gland

TheVisualMD

Endocrine Glands

CNX Openstax

4:11

Thyroid problems - most common thyroid problems, symptoms and treatment

Healthchanneltv / cherishyourhealthtv/YouTube

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

1:34

What Is A Thyroid Nodule?

Swedish/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

Thyroid-Stimulating Immunoglobulin Test

Thyroid-Stimulating Immunoglobulin Test

Also called: TSI, Human Thyroid Stimulator, HTS, Long-acting Thyroid Stimulator, LATS

Thyroid-stimulating immunoglobulins (TSIs) are antibodies that mistakenly attack and overstimulate the thyroid gland, potentially leading to damage, long-term inflammation (thyroiditis) and disruption of thyroid function.

Thyroid-Stimulating Immunoglobulin Test

Also called: TSI, Human Thyroid Stimulator, HTS, Long-acting Thyroid Stimulator, LATS

Thyroid-stimulating immunoglobulins (TSIs) are antibodies that mistakenly attack and overstimulate the thyroid gland, potentially leading to damage, long-term inflammation (thyroiditis) and disruption of thyroid function.

{"label":"Thyroid-Stimulating Immunoglobulin Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"(i.U.)\/L","code":"[IU]\/L","name":"international unit per liter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":0.55},"text":"Normal results may slightly vary from laboratory to laboratory.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":0.55,"max":3},"text":"Your levels of TSI are elevated. Talk to your doctor to know what your results mean in your specific case. ","conditions":["Hyperthyroidism","Graves\u2019 disease","Hashitoxicosis","Neonatal thyrotoxicosis","Autoimmune thyrotoxicosis",""]}],"value":0.3}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
(i.U.)/L
0.55
Your result is Normal.
Normal results may slightly vary from laboratory to laboratory.
Related conditions
Your doctor may want to order this test if you have signs or symptoms of an overactive thyroid (hyperthyroidism) or in the following situations:
- As an aid in the diagnosis of Graves' disease.
- To monitor treatment for Graves’ disease.
- Determine the cause of autoimmune thyrotoxicosis
- In pregnant women, to predict hyperthyroidism in the fetus.
Normal reference ranges are from 0.00 to 0.55 IU/L.
An increased level may indicate:
- Hyperthyroidism
- Graves’ disease, which is the most common cause of hyperthyroidism
- Hashitoxicosis (very rare)
- Neonatal thyrotoxicosis
- Autoimmune thyrotoxicosis
You should visit your doctor if you experience signs and symptoms of hyperthyroidism, such as:
- Inexplicable and sudden weight loss
- Rapid heartbeat (tachycardia)
- Heart pounding (palpitations)
- Increased appetite
- Nervousness
- Anxiety
- Trembling in your hands and fingers
- Sweating
- Changes in menstrual patterns
- Changes in bowel patterns
- Increased sensitivity to heat
- Difficulty sleeping
- Skin thinning
- Fine, brittle hair
1. 140749: Thyroid-stimulating Immunoglobulin (TSI) | LabCorp [accessed on Oct 04, 2018]
2. TSI test: MedlinePlus Medical Encyclopedia [accessed on Oct 04, 2018]
3. TSI - Clinical: Thyroid-Stimulating Immunoglobulin (TSI), Serum [accessed on Oct 04, 2018]
4. Hyperthyroidism - Symptoms and causes - Mayo Clinic [accessed on Oct 04, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (10)

The classic finding of exophthalmos and lid retraction in Graves' disease

Proptosis and Lid Retraction from Graves Disease : Photograph showing a classic finding of Graves' Disease, proptosis and lid retraction.

Image by Jonathan Trobe, M.D. - University of Michigan Kellogg Eye Center

What is Graves' ophthalmopathy?

Magnetic Resonance Imaging of the orbits, showing congestion of the retro-orbital space and enlargement of the extraocular muscles (arrows), consistent with the diagnosis of Graves' Ophthalmopathy.

Image by Huy A Tran and Glenn EM Reeves

What are the symptoms of Graves' disease?

Graves' disease symptoms

Image by Original uploader was Madhero88 at en.wikipedia

Who is more likely to develop hyperthyroidism?

Anxiety, Symptom of Hyperthyroidism : The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces hormones two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. Hyperthyroidism (when too much hormone is produced) is often caused by an autoimmune disorder called Graves' disease, in which antibodies produced by the immune system over-stimulate the thyroid; symptoms include anxiety and mood swings.

Image by TheVisualMD

Hyperthyroidism

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces hormones two hormones, thyroxine (T4) and triiodothyronine (T3), that help maintain body temperature, heart rate, moods, and metabolism. Hyperthyroidism (when too much hormone is produced) is often caused by an autoimmune disorder called Graves' disease, in which antibodies produced by the immune system over-stimulate the thyroid.

Image by TheVisualMD

Thyroid Stimulating Hormone (TSH)

The thyroid is a small, butterfly-shaped gland located at the base of the neck that produces hormones that help maintain body temperature, heart rate, moods, and metabolism. Hyperthyroidism (when too much hormone is produced) is often caused by an autoimmune disorder called Graves' disease, in which antibodies produced by the immune system over-stimulate the thyroid. The production of thyroid hormones is under the control of a hormone called TSH (thyroid-stimulating hormone) produced by the pituitary gland.

Image by TheVisualMD

What is Graves Disease?

Video by TriHealth Cincinnati/YouTube

Graves' Disease Education

Video by Jennifer Riccobono/YouTube

Autoimmune Diseases - Causes, Symptoms, Treatments & More…

Video by Rehealthify/YouTube

What Are Autoimmune Diseases?

Video by Autoimmune Association/YouTube

The classic finding of exophthalmos and lid retraction in Graves' disease

Jonathan Trobe, M.D. - University of Michigan Kellogg Eye Center

What is Graves' ophthalmopathy?

Huy A Tran and Glenn EM Reeves

What are the symptoms of Graves' disease?

Original uploader was Madhero88 at en.wikipedia

Who is more likely to develop hyperthyroidism?

TheVisualMD

Hyperthyroidism

TheVisualMD

Thyroid Stimulating Hormone (TSH)

TheVisualMD

2:25

What is Graves Disease?

TriHealth Cincinnati/YouTube

9:07

Graves' Disease Education

Jennifer Riccobono/YouTube

2:04

Autoimmune Diseases - Causes, Symptoms, Treatments & More…

Rehealthify/YouTube

2:01

What Are Autoimmune Diseases?

Autoimmune Association/YouTube

Calcitonin Test

Calcitonin Test

Also called: Thyrocalcitonin, Human Calcitonin, hCT

A calcitonin test checks the level of calcitonin, a thyroid hormone, in your blood. Calcitonin helps control the level of calcium in your blood. The test is mainly used to help diagnose and monitor medullary thyroid cancer.

Calcitonin Test

Also called: Thyrocalcitonin, Human Calcitonin, hCT

A calcitonin test checks the level of calcitonin, a thyroid hormone, in your blood. Calcitonin helps control the level of calcium in your blood. The test is mainly used to help diagnose and monitor medullary thyroid cancer.

{"label":"Calcitonin Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"pg\/mL","code":"pg\/mL","name":"picogram per milliliter"}],"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":8.4},"text":"Your results are normal. Therefore, it is unlikely that you have C-cell hyperplasia or medullary thyroid cancer. Reference ranges can vary depending on the laboratory and the method used for testing.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":8.4,"max":20},"text":"Your calcitonin levels are high. This is a good indicator of C-cell hyperplasia or medullary thyroid cancer. Further testing may be necessary.","conditions":["Medullary cancer of the thyroid","C-cell hyperplasia","Insulinoma","Lung cancer","VIPoma"]}],"value":4.2}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
pg/mL
8.4
Your result is Normal.
Your results are normal. Therefore, it is unlikely that you have C-cell hyperplasia or medullary thyroid cancer. Reference ranges can vary depending on the laboratory and the method used for testing.
Related conditions
A calcitonin test measures the level of calcitonin in a sample of your blood. Calcitonin is a hormone that helps control the level of calcium in your blood. Calcitonin is made in your thyroid gland by cells called "C cells." Your thyroid is a small, butterfly-shaped gland in your neck.
Normally, you have a small amount of calcitonin in your blood. But if you have too much, it may be a sign of:
- Medullary thyroid cancer (MTC), a rare cancer that happens when C cells in your thyroid grow out of control. C cells grow in the inside part of your thyroid, which is called the medulla.
- C-cell hyperplasia, a rare condition that causes abnormal growth of C cells in your thyroid. C-cell hyperplasia can turn into medullary thyroid carcinoma.
Your health care provider may order a calcitonin test if you have symptoms of these conditions or if they run in your family.
A calcitonin test is most often used to:
- Help diagnose C-cell hyperplasia and medullary thyroid cancer in people who have symptoms
- Find out if treatment for medullary thyroid cancer is working
- Check whether medullary thyroid cancer has returned after treatment
- Screen people who have a high risk of medullary thyroid cancer. The risk is high for people who have a family history of a rare genetic disorder called multiple endocrine neoplasia type 2 (MEN 2).
There are different types of MEN 2 that often cause tumors in certain glands that make hormones, including your thyroid. All types of MEN 2 increase your risk of medullary thyroid cancer. MEN 2 is caused by changes in a gene called RET. Changes in genes are also called gene variants or mutations.
You can inherit MEN 2 - and an increased risk for medullary thyroid cancer - if either of your parents passed a changed RET gene down to you. If MEN 2 runs in your family, regular calcitonin tests can help find cancer early when it may be easier to treat.
You may need a calcitonin test to help check for medullary thyroid cancer or C-cell hyperplasia if:
- You have symptoms of either condition which may include:
  A lump in the front of your neck
  Swollen lymph nodes in your neck (also called "swollen glands")
  Pain in your throat
  Trouble swallowing or breathing
  A change in your voice, such as hoarseness
  A long-lasting cough when you don't have a cold
  Diarrhea
- You have symptoms of multiple endocrine neoplasia type 2 (MEN 2). MEN 2 can affect your thyroid, adrenal, and parathyroid glands. Symptoms depend on which glands are affected. They may include:
  Fatigue
  Depression
  Aches and pains in bones and joints
  Nausea and vomiting
  Increased thirst and urination (peeing)
  High blood pressure
  Headaches
  Arrythmia (a problem with the rate or rhythm of your heart)
  Sweating
- You have a family history of MEN 2, which increases your risk of developing medullary thyroid cancer. If MEN 2 runs in your family, you and your family members, including children, may need regular calcitonin tests to help find cancer before you have symptoms. Your provider may also suggest a blood test to check for changes in your RET genes that cause MEN 2.
If you've been diagnosed with medullary thyroid cancer, you'll need calcitonin testing to:
- Find out how well your treatment is working.
- Check whether the cancer has come back after you finish treatment.
The meaning of your calcitonin test results depends on the reason you were tested. If you had a calcitonin test:
To help diagnose or screen for medullary thyroid cancer or C-cell hyperplasia:
- A normal calcitonin level may mean that you don't have either condition, but it doesn't rule them out. That's because medullary thyroid cancer and C-cell hyperplasia don't always cause high calcitonin. Your provider may order other tests to learn more.
- A high calcitonin level means that the C cells in your thyroid are making too much calcitonin. The higher the level, the more likely it is that you have medullary thyroid cancer or C-cell hyperplasia. But high calcitonin levels may be caused by other conditions, including certain other cancers, certain medicines, and pregnancy. To make a diagnosis, your provider will consider other information, including other test results.
- A low calcitonin level is not known to be a medical problem.
To monitor treatment for medullary thyroid cancer or to check whether cancer has come back after treatment: The meaning of your test results depends on the type of treatment you're having or had. Treatment usually starts with surgery to remove your thyroid gland. Other treatments include radiation therapy, chemotherapy, and/or medicines.
In general:
- Calcitonin levels that decrease and stay low over time usually mean that your treatment is helping.
- A calcitonin level that decreases but is still higher than normal may mean that you still have some cancer tissue left in your body. You may need more tests and treatment.
- A calcitonin level that increases over time usually means that your cancer has returned or spread to other parts of your body.
Ask your provider to explain what your test results mean for your health.
1. 004895: Calcitonin (Thyrocalcitonin) | LabCorp [accessed on Nov 12, 2018]
2. Calcitonin Test: MedlinePlus Medical Test [accessed on Mar 09, 2023]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (5)

Calcitonin

BruceBlaus

Thyroid Gland

TheVisualMD

Thyroid Gland and Parathyroid Gland

TheVisualMD

Parathyroid Gland

OpenStax College

Parathyroid Gland

BodyParts3D is made by DBCLS

Thyroid Scan

Thyroid Scan

Also called: Thyroid Scintigraphy

A thyroid scan uses a small amount of radioactive material called radiotracer to examine the structure and function of the thyroid gland. This test is often done together with a thyroid uptake test.

Thyroid Scan

Also called: Thyroid Scintigraphy

A thyroid scan uses a small amount of radioactive material called radiotracer to examine the structure and function of the thyroid gland. This test is often done together with a thyroid uptake test.

{"label":"Thyroid Scan Reference Range","scale":"lin","step":0.25,"hideunits":true,"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":1},"text":"Normal scan results will show that the thyroid gland has an even gray color without darker or lighter areas, is in the proper location, and has a correct size and shape. ","conditions":[]},{"flag":"abnormal","label":{"short":"Abnormal","long":"Abnormal","orientation":"horizontal"},"values":{"min":1,"max":2},"text":"Abnormalities in the gland\u2019s shape, size, or location may indicate a tumor.<br \/>\n","conditions":["Thyroid tumor","Thyroid nodules"]}],"value":0.5}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
Your result is Normal.
Normal scan results will show that the thyroid gland has an even gray color without darker or lighter areas, is in the proper location, and has a correct size and shape.
Related conditions
Your doctor may want to order this test to:
- Diagnose problems with the thyroid gland, such as nodules or goiter.
- Find the cause of an overactive thyroid gland.
- Investigate whether any cancer has spread beyond the thyroid gland.
- To evaluate changes in the thyroid gland due to surgery, medication, radiotherapy or chemotherapy.
Normal
Normal scan results will show that the thyroid gland has an even gray color without darker or lighter areas, is in the proper location, and has a correct size and shape.
Uptake results show the percentage of iodine that has collected in your thyroid gland. The higher the iodine uptake, the more active is the thyroid gland. Normal values at 6 and 24 hours are:
- At 6 hours: 3% to 16%
- At 24 hours: 8% to 25%
Normal reference ranges may vary slightly among different labs.
Abnormal
Abnormalities in the gland’s shape, size, or location may indicate a tumor.
If your gland collects too much iodine, it will look like a darker area (hot area) in the scan. This may be due to an overactive thyroid gland. Other causes include:
- Graves’ disease
- Toxic nodular goiter (enlarged thyroid gland that contains nodules producing too much thyroid hormone)
- Toxic adenoma (single thyroid nodule that is producing too much thyroid hormone)
If your gland collects too little iodine, it will look like a lighter area (cold area) in the scan. This may be due to inflammation or other damage to the thyroid. Other causes include:
- Factitious hyperthyroidism (taking too much thyroid hormone medicine or supplements)
- Iodine overload
- Subacute thyroiditis (inflammation of the thyroid gland)
- Silent (painless) thyroiditis
- Intake of amiodarone (medicine to treat some kinds of heart disease)
1. Thyroid scan: MedlinePlus Medical Encyclopedia [accessed on Dec 17, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (17)

Thyroid Disease in Women

Document by Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Document by Office on Women's Health, U.S. Department of Health and Human Services

Document by Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam`s apple. Hormones produced by the thyroid gland have an enormous impact on many aspects of metabolism.

Image by TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

The thyroid gland’s production of thyroid hormones (T3 and T4) is regulated by thyroid-stimulating hormone (TSH), which is made by the pituitary gland.

Image by NIDDK Image Library

Thyroid Gland

The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Image by CNX Openstax

Thyroid Gland

Image by CFCF

Setting the Pace: Thyroid & Metabolism

Image by TheVisualMD

Thyroid Gland

Illustration of the Posterior thyroid

Image by US GOV

Parathyroid Gland

Image showing thyroid/parathyroid in color against skeleton and various organs.

Image by BodyParts3D is made by DBCLS

Benign Tumor

Thyroid adenoma

Image by myself

Thyroid Cancer

While thyroid cancer is very treatable with surgery and other therapies, it is one of the fastest growing cancers in the United States.

Image by Darryl Leja, NHGRI

Thyroid Gland

The thyroid gland (left lobe, right lobe, and thymus) is labeled in the body.

Image by National Cancer Institute / Don Bliss (Illustrator)

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

What Is A Thyroid Nodule?

Video by Swedish/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

Thyroid Disease in Women

Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Office on Women's Health, U.S. Department of Health and Human Services

Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

TheVisualMD

Thyroid Gland

TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

NIDDK Image Library

Thyroid Gland

CNX Openstax

Thyroid Gland

CFCF

Setting the Pace: Thyroid & Metabolism

TheVisualMD

Thyroid Gland

US GOV

Parathyroid Gland

BodyParts3D is made by DBCLS

Benign Tumor

myself

Thyroid Cancer

Darryl Leja, NHGRI

Thyroid Gland

National Cancer Institute / Don Bliss (Illustrator)

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

1:34

What Is A Thyroid Nodule?

Swedish/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

Thyroid Uptake Test

Thyroid Uptake Test

Also called: Iodine Uptake Scan, Radioactive Iodine Uptake, RAIU

A thyroid uptake test measures how much radioactive iodine is taken up by your thyroid gland in a certain time period. It tests thyroid function and is often done together with a thyroid scan test.

Thyroid Uptake Test

Also called: Iodine Uptake Scan, Radioactive Iodine Uptake, RAIU

A thyroid uptake test measures how much radioactive iodine is taken up by your thyroid gland in a certain time period. It tests thyroid function and is often done together with a thyroid scan test.

{"label":"Thyroid Uptake Reference Range","scale":"lin","step":0.1,"hideunits":false,"units":[{"printSymbol":"%","code":"%","name":"percent"}],"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":3},"text":"If your gland collects too little iodine, it will look like a lighter area (cold area) in the scan. This may be due to inflammation or other damage to the thyroid. ","conditions":["Factitious hyperthyroidism","Iodine overload","Subacute thyroiditis","Silent thyroiditis","Intake of amiodarone"]},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":3,"max":16},"text":"Normal results at 6 hours after swallowing the radioactive iodine are 3% to 16%.","conditions":[]},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":16,"max":100},"text":"If your gland collects too much iodine, it will look like a darker area (hot area) in the scan. This may be due to an overactive thyroid gland.","conditions":["Hyperthyroidism","Graves\u2019 disease","Toxic nodular goiter","Toxic adenoma"]}],"value":9.5}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
%
3
16
Your result is Normal.
Normal results at 6 hours after swallowing the radioactive iodine are 3% to 16%.
Related conditions
Your doctor may want to order this test to:
- Diagnose problems with the thyroid gland, such as nodules or goiter.
- Find the cause of an overactive thyroid gland.
- Investigate whether any cancer has spread beyond the thyroid gland.
- To evaluate changes in the thyroid gland due to surgery, medication, radiotherapy or chemotherapy.
Normal
Normal scan results will show that the thyroid gland has an even gray color without darker or lighter areas, is in the proper location, and has a correct size and shape.
Uptake results show the percentage of iodine that has collected in your thyroid gland. The higher the iodine uptake, the more active is the thyroid gland. Normal values at 6 and 24 hours are:
- At 6 hours: 3% to 16%
- At 24 hours: 8% to 25%
Normal reference ranges may vary slightly among different labs.
Abnormal
Abnormalities in the gland’s shape, size, or location may indicate a tumor.
If your gland collects too much iodine, it will look like a darker area (hot area) in the scan. This may be due to an overactive thyroid gland. Other causes include:
- Graves’ disease
- Toxic nodular goiter (enlarged thyroid gland that contains nodules producing too much thyroid hormone)
- Toxic adenoma (single thyroid nodule that is producing too much thyroid hormone)
If your gland collects too little iodine, it will look like a lighter area (cold area) in the scan. This may be due to inflammation or other damage to the thyroid. Other causes include:
- Factitious hyperthyroidism (taking too much thyroid hormone medicine or supplements)
- Iodine overload
- Subacute thyroiditis (inflammation of the thyroid gland)
- Silent (painless) thyroiditis
- Intake of amiodarone (medicine to treat some kinds of heart disease)
1. Radioactive iodine uptake: MedlinePlus Medical Encyclopedia [accessed on Dec 17, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (17)

Thyroid Disease in Women

Document by Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Document by Office on Women's Health, U.S. Department of Health and Human Services

Document by Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

The thyroid and the hormones it produces, for example, are under control of a hormone called TSH (thyroid-stimulating hormone), which is produced by the pituitary gland. The pituitary gland is often referred to as the "master gland" because it regulates the activities of other endocrine glands. The pituitary gland, however, takes its orders from the hypothalamus, which decides which particular hormones the pituitary should release and when.

Image by TheVisualMD

Thyroid Gland

The thyroid is a small, butterfly-shaped gland located at the base of the neck, just below the Adam`s apple. Hormones produced by the thyroid gland have an enormous impact on many aspects of metabolism.

Image by TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

The thyroid gland’s production of thyroid hormones (T3 and T4) is regulated by thyroid-stimulating hormone (TSH), which is made by the pituitary gland.

Image by NIDDK Image Library

Thyroid Gland

The thyroid gland is located in the neck where it wraps around the trachea. (a) Anterior view of the thyroid gland. (b) Posterior view of the thyroid gland. (c) The glandular tissue is composed primarily of thyroid follicles. The larger parafollicular cells often appear within the matrix of follicle cells. LM × 1332. (Micrograph provided by the Regents of University of Michigan Medical School © 2012)

Image by CNX Openstax

Thyroid Gland

Image by CFCF

Setting the Pace: Thyroid & Metabolism

Image by TheVisualMD

Thyroid Gland

Illustration of the Posterior thyroid

Image by US GOV

Parathyroid Gland

Image showing thyroid/parathyroid in color against skeleton and various organs.

Image by BodyParts3D is made by DBCLS

Benign Tumor

Thyroid adenoma

Image by myself

Thyroid Cancer

While thyroid cancer is very treatable with surgery and other therapies, it is one of the fastest growing cancers in the United States.

Image by Darryl Leja, NHGRI

Thyroid Gland

The thyroid gland (left lobe, right lobe, and thymus) is labeled in the body.

Image by National Cancer Institute / Don Bliss (Illustrator)

Thyroid gland - What's the function of the thyroid?

Video by Healthchanneltv / cherishyourhealthtv/YouTube

What Is A Thyroid Nodule?

Video by Swedish/YouTube

How a thyroid gland can become underactive

Video by Bupa Health UK/YouTube

Thyroid Disease in Women

Office on Women's Health, U.S. Department of Health and Human Services

OWH Graves’ Disease Factsheet

Office on Women's Health, U.S. Department of Health and Human Services

Office on Women's Health, U.S. Department of Health and Human Services

Importance of Thyroid Gland

TheVisualMD

Thyroid Gland

TheVisualMD

Drawing of the head and neck with the thyroid, pituitary gland, TSH, and T3–T4 labeled. Arrows show the direction of TSH from the pituitary gland to the thyroid gland and of T3–T4 from the thyroid to the pituitary gland

NIDDK Image Library

Thyroid Gland

CNX Openstax

Thyroid Gland

CFCF

Setting the Pace: Thyroid & Metabolism

TheVisualMD

Thyroid Gland

US GOV

Parathyroid Gland

BodyParts3D is made by DBCLS

Benign Tumor

myself

Thyroid Cancer

Darryl Leja, NHGRI

Thyroid Gland

National Cancer Institute / Don Bliss (Illustrator)

1:55

Thyroid gland - What's the function of the thyroid?

Healthchanneltv / cherishyourhealthtv/YouTube

1:34

What Is A Thyroid Nodule?

Swedish/YouTube

2:24

How a thyroid gland can become underactive

Bupa Health UK/YouTube

Prolactin Test

Prolactin Test

Also called: PRL, Prolactin Blood Test, Hypoprolactinemia Test, Hyperprolactinemia Test

The prolactin test measures levels of the hormone prolactin (PRL) in a sample of your blood. Normally, the level of prolactin in the blood increases markedly during pregnancy and breastfeeding. High levels in nonpregnant women and men may be a sign of a health problem.

Prolactin Test

Also called: PRL, Prolactin Blood Test, Hypoprolactinemia Test, Hyperprolactinemia Test

The prolactin test measures levels of the hormone prolactin (PRL) in a sample of your blood. Normally, the level of prolactin in the blood increases markedly during pregnancy and breastfeeding. High levels in nonpregnant women and men may be a sign of a health problem.

{"scale":"lin","step":0.1,"hideunits":false,"items":[{"flag":"abnormal","label":{"short":"Low","long":"Low","orientation":"horizontal"},"values":{"min":0,"max":4.8},"text":"Your prolactin levels are low. This is a rare occurrence. Talk to your doctor to know what this result means in your specific case. "},{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":4.8,"max":23.3},"text":"Prolactin levels are normally high for pregnant women and new mothers. Levels are normally low for nonpregnant women and for men."},{"flag":"abnormal","label":{"short":"High","long":"High","orientation":"horizontal"},"values":{"min":23.3,"max":50},"text":"Your prolactin levels are high, this is normal during pregnancy and after childbirth, but in any other situation it can be related to a wide variety of conditions. Talk to your doctor to know what this result means in your specific case. "}],"units":[{"printSymbol":"ng\/mL","code":"ng\/mL","name":"nanogram per milliliter"}],"disclaimer":"Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are \"within normal limits.\""}[{"abnormal":0},{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
ng/mL
4.8
23.3
Your result is Low.
Your prolactin levels are low. This is a rare occurrence. Talk to your doctor to know what this result means in your specific case.
Related conditions
A prolactin (PRL) test measures the level of prolactin in a sample of your blood. Prolactin is a hormone produced by the pituitary gland, a small gland at the base of the brain. Hormones are chemical messengers in your bloodstream that control the actions of certain cells or organs.
Prolactin affects many body processes. But its main role is to signal breast tissue to grow during pregnancy and make milk for breastfeeding after birth. So, prolactin levels in pregnant women and new mothers are normally high.
In nonpregnant women and men, prolactin levels are normally low.
Having higher-than-normal prolactin levels (hyperprolactinemia) can affect the body in different ways:
- In women, it can affect how the ovaries work and can cause menstrual problems and infertility.
- In men, it can affect how the testicles work and can cause a lower sex drive and erectile dysfunction (ED). Also known as impotence, ED is the inability to get or maintain an erection.
- In men and women who are not pregnant or breastfeeding, it can signal your body to start making breastmilk.
Higher-than-normal prolactin levels can have different causes:
- Prolactinoma, a benign (noncancerous) tumor growing on the pituitary gland. This is the most common cause. This type of tumor makes prolactin, which leads to higher-than-normal levels of prolactin in the blood.
- Certain medicines.
- Certain health conditions, such as hypothyroidism (underactive thyroid), kidney disease, and chest injuries
- Other pituitary gland tumors.
A prolactin test can't show the cause of higher-than-normal prolactin levels. But finding out what your levels are can help your health care provider decide which other tests you need to diagnose the cause of your symptoms.
Other names: PRL test, prolactin blood test
A prolactin test is most often used with other tests to help:
- Diagnose a prolactinoma
- Find the cause of irregular menstrual periods
- Find the cause of infertility in men and women
- Find the cause of a man's low sex drive and/or erectile dysfunction
- Monitor a known prolactinoma to see if:
  Treatment is working.
  The tumor has come back after treatment.
You may need a prolactin levels test if you are having symptoms that could be caused by higher-than-normal prolactin levels. The symptoms are different for women and men.
In women, symptoms may include:
- Changes in menstruation (irregular periods or absence of periods)
- Production of breast milk when not pregnant or breastfeeding
- Nipple discharge
- Infertility
Symptoms also depend on whether you have gone through menopause, which is when your periods stop, normally around age 50.
In men, symptoms may include:
- Nipple discharge
- Erectile dysfunction/impotence
- Enlarged breasts (gynecomastia)
- Decreased facial and body hair
- Low sex drive
If you have higher-than-normal levels of prolactin because of a prolactinoma, you may also have other symptoms. A prolactinoma that is not treated can grow large enough that it presses against nearby parts of the pituitary gland and the brain. This can cause:
- Headaches
- Changes in vision, if the tumor is pressing on the optic nerve (the nerve at the back of the eye)
- Low levels of other pituitary hormones, such as thyroid hormones and cortisol
If you've already been diagnosed with high prolactin levels from a prolactinoma, you may need prolactin testing to check whether your treatment is working. After treatment, you may be retested to see if the tumor has come back.
To understand what the results of your prolactin levels test mean, your provider will consider your symptoms, sex, and medical history, and the results of any other tests you had.
In general, for men and women who aren't pregnant or breastfeeding, higher-than-normal prolactin levels may be a sign of many types of conditions, such as:
- Prolactinoma or another pituitary disorder.
- A disease of the hypothalamus. The hypothalamus is an area of the brain that controls the pituitary gland and other body functions.
- Hypothyroidism.
- Cirrhosis (scarring of the liver).
- Kidney disease.
- Polycystic ovary syndrome (PCOS) in women.
If your results show high prolactin levels, your provider will usually order other blood tests to help diagnose the cause. If your provider thinks you may have a prolactinoma, you may also have an MRI (magnetic resonance imaging) scan to check your pituitary gland for tumors.
Treatment for high prolactin levels depends on the cause. Treatment is usually medicine. Surgery may be needed for certain pituitary tumors.
Higher-than-normal prolactin levels don't always mean you have a medical condition that needs treatment. Diets high in protein and certain medicines can cause high levels. Small increases in prolactin may be caused by stress, exercise, and even having sex. So, depending on your symptoms and medical history, your provider may suggest testing you again to see if your prolactin levels remain high.
Lower-than-normal prolactin levels are rare but may be a sign of a pituitary disorder. Without enough prolactin, a woman may not make enough milk to breastfeed after birth. This is usually the only symptom of abnormally low prolactin levels.
If you have questions about your results, talk with your provider.

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (12)

Prolactin Rejected from Receptor in Lactocyte

On the walls of the lactocytes (milk-producing cells) are prolactin receptors that allow prolactin in the bloodstream to move into the lactocytes and stimulate the synthesis of breast milk components. Scientists theorize that when the alveolus is full of milk, the walls stretch and alter the shape of prolactin receptors so that prolactin cannot activate those receptor sites. This causes the rate of milk synthesis to slow. As milk empties from the alveolus, on the other hand, prolactin receptors return to their normal shape and allow prolactin to bind to the receptors (as shown in image), triggering milk production to increase.

Image by TheVisualMD

Breast Function

The function of the breast is to produce milk and colostrum for the infant. The breast undergoes many important changes when a woman becomes pregnant, in preparation for producing milk. Estrogen and progesterone stimulate cell growth and development of the breast. Special hormones called prolactin and somatomammotrophin, produced during pregnancy, also play a role. The cells in the glands of the breast tissue change shape, become bigger, and increase in number. Later on in the pregnancy, the lobules start to produce milk, which begins to accumulate in the ducts. Muscle tissue around the lobules helps to squeeze the milk into the ducts. During breastfeeding, glands on the areola secrete a fluid to lubricate the nipple, and muscles in the nipple allow it to become erect. A protein and antibody-rich fluid called colostrum is produced during the last weeks of pregnancy and during the first few episodes of nursing.

Image by TheVisualMD

Breast Milk

Image by TheVisualMD

Breast Milk

Image by TheVisualMD

Nourishing Body & Bond

Mother’s milk is a marvel. It is an extraordinarily complex fluid, assembled in the mother’s body through a long series of interconnected steps. Breast milk is also uniquely adapted to the changing nutritional needs of a baby. At birth, breast milk is perfectly suited for the infant’s vulnerable immune system and immature digestive tract. As the baby develops, the composition of breast milk and its proportions of fat, protein, and carbohydrates change accordingly to fuel growth and development.

Image by TheVisualMD

Mammary Gland

For some hormones, the effects are felt by many unrelated tissues. Prolactin, for example, not only stimulates milk production in the breasts, but is essential for the development of tissue in the ovary that secretes progesterone, which is necessary for pregnancy. Prolactin may also help to regulate the immune response.

Image by TheVisualMD

Prolactin

For some hormones, the effects are felt by many unrelated tissues. Prolactin, for example, not only stimulates milk production in the breasts, but is essential for the development of tissue in the ovary that secretes progesterone, which is necessary for pregnancy. Prolactin may also help to regulate the immune response.

Image by TheVisualMD

Breastfeeding Cycle

During breastfeeding, the baby's sucking stimulates nerves in the mother's nipple and areola. The nerves send a signal to the mother's hypothalamus and pituitary gland. The pituitary gland releases the hormones prolactin and oxytocin, which travel through the mother's bloodstream to the mammary gland to stimulate milk production and ejection (let-down reflex).

Image by TheVisualMD

Prolactinoma

The pituitary gland sits in the sella turcica.

Image by National Endocrine and Metabolic Diseases Information Service, NIH.

This browser does not support the video element.

Feeding Cycle: Prolactin & Oxytocin

At first the grainy, black-and-white images could be mistaken for a time-lapse video of the erosion of a riverbed. But when Donna Geddes, professor of biomedical sciences at the University of Western Australia (UWA), explains what the moving images are, it becomes clear just how remarkable this video footage is. Using ultrasound imaging techniques, Geddes and her colleagues at UWA have captured in real time the actual flow of milk through the ducts in a woman’s breast. Look closely, says Geddes, and you’ll notice “small white flecks (milk-fat globules) are seen moving within the duct towards the nipple. Also, sometimes surrounding ducts are seen to dilate...and some small ducts that are not obvious prior to milk ejection become visible.”

Video by TheVisualMD

This browser does not support the video element.

Mother's Milk

Video by TheVisualMD

Lactating Breast Structure

Schematic diagram showing lateral view of Structure of Human Lactating breast. The development of glandular structure further occurs mainly under the influence of Hormone - Progesterone. After birth of baby milk production and secretion starts under the influence of Hormones - Prolactin and Oxytocin respectively.

Image by Rajendra prabhune/Wikimedia

Prolactin Rejected from Receptor in Lactocyte

TheVisualMD

Breast Function

TheVisualMD

Breast Milk

TheVisualMD

Breast Milk

TheVisualMD

Nourishing Body & Bond

TheVisualMD

Mammary Gland

TheVisualMD

Prolactin

TheVisualMD

Breastfeeding Cycle

TheVisualMD

Prolactinoma

National Endocrine and Metabolic Diseases Information Service, NIH.

1:31

Feeding Cycle: Prolactin & Oxytocin

TheVisualMD

3:39

Mother's Milk

TheVisualMD

Lactating Breast Structure

Rajendra prabhune/Wikimedia

Karyotype Test

Karyotype Test

Also called: Chromosome Analysis, Chromosome Karyotype, Chromosome Studies, Chromosome Testing, Karyotyping, Karyotype Genetic Test

A karyotype test is a type of genetic testing. It looks at the size, shape, and number of your chromosomes. Chromosomes are parts of cells that contain genes. If the number or structure of your chromosomes is not normal, it can indicate a genetic disease.

Karyotype Test

Also called: Chromosome Analysis, Chromosome Karyotype, Chromosome Studies, Chromosome Testing, Karyotyping, Karyotype Genetic Test

A karyotype test is a type of genetic testing. It looks at the size, shape, and number of your chromosomes. Chromosomes are parts of cells that contain genes. If the number or structure of your chromosomes is not normal, it can indicate a genetic disease.

{"label":"Karyotype Reference Range","scale":"lin","step":0.25,"hideunits":true,"items":[{"flag":"normal","label":{"short":"Normal","long":"Normal","orientation":"horizontal"},"values":{"min":0,"max":1},"text":"A normal human karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes (allosomes). Normal karyotypes for females contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY.","conditions":[]},{"flag":"abnormal","label":{"short":"Abnormal","long":"Abnormal","orientation":"horizontal"},"values":{"min":1,"max":2},"text":"If you have more or fewer chromosomes than 46, or if there is anything unusual about the size or shape of your chromosomes, it can mean you have a\u00a0genetic disease. <br \/>\n<br \/>\nIf you were tested because you have a certain type of cancer or blood disorder, your results can show whether or not your condition is caused by a chromosomal defect.","conditions":["Chromosome abnormalities","Sex chromosome abnormalities","45,X\/46,XY mosaicism","47,XYY syndrome","48,XXXY syndrome","48,XXYY syndrome","49,XXXXY syndrome","Down syndrome (47,XX,+21 or 47,XY,+21)","Edwards syndrome (47,XX,+18 or 47,XY,+18)","Klinefelter syndrome (47,XXY)","Patau syndrome (47,XX,+13 or 47,XY,+13)","Turner syndrome (45,X)"]}],"value":0.5}[{"normal":0},{"abnormal":0}]
Use the slider below to see how your results affect your health.
Your result is Normal.
A normal human karyotype contains 22 pairs of autosomal chromosomes and one pair of sex chromosomes (allosomes). Normal karyotypes for females contain two X chromosomes and are denoted 46,XX; males have both an X and a Y chromosome denoted 46,XY.
Related conditions
A karyotype test is a type of genetic testing. It looks at the size, shape, and number of chromosomes in a sample of cells from your body. Chromosomes are found in the cell nucleus, which is like the command center of a cell. Chromosomes contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works.
You inherit your chromosomes from your parents. Normally, all your cells (except for egg and sperm cells) have a set of the same 46 chromosomes. The chromosomes are grouped into 23 pairs. Each pair has two chromosomes, one coming from each parent. You may develop certain genetic disorders if your cells:
- Are missing whole chromosomes or pieces of chromosomes
- Have extra chromosomes or extra pieces of chromosomes
A karyotype test checks the chromosomes in your cells to:
- See whether you have a full set of 46 chromosomes. Having too many or too few chromosomes can cause serious problems with health, growth, and normal development, such as Down syndrome (extra chromosome 21) and Turner syndrome (missing X chromosome).
- Look for changes in the structure of chromosomes, such as broken, missing, or extra parts. These changes may cause a wide variety of problems depending on which chromosome is affected. But some changes in chromosomes don't cause problems.
Certain chromosome problems are present from birth. Chromosome problems can also develop in certain cells after birth. These problems can cause specific types of cancer.
Other names: genetic testing, chromosome testing, chromosome studies, cytogenetic analysis
A karyotype test looks for unusual changes in chromosomes. It may be used to:
- Check you and/or your family members for specific chromosome problems if you:
  Have a genetic disorder that runs in your family
  Have symptoms that may be from a genetic disorder
- Check an unborn baby for chromosome problems
- Find out if abnormal chromosomes are causing problems having children, including:
  Male or female infertility
  Miscarriages, if you have lost two or more pregnancies before 20 weeks
  Stillbirth
- Help diagnose and/or make treatment decisions for certain types of cancer and blood disorders
You may need a karyotype test if:
- You're planning to have children or are pregnant:
  To learn whether you and/or your partner have abnormal chromosomes that you could pass on to a baby
  To find out why you're having problems getting pregnant or having miscarriages
  To check your unborn baby for genetic disorders, especially if the baby has a high risk for problems. The risk may be high if:
  The pregnant parent is age 35 or older. The overall risk of genetic birth defects is small, but the risk increases after age 35.
  Either parent has a genetic disorder, a family history of a genetic disorder, or another child with a genetic disorder.
  The results of certain prenatal screening tests weren't normal.
- You have a family history of a chromosomal disorder and want to know your risk for developing the disorder.
- You and/or your child have symptoms of a genetic disorder. Each type of genetic disorder has different symptoms. Karyotype testing may be needed to make a diagnosis.
- You've been diagnosed with certain cancers or blood disorders that often involve changes in chromosomes. These changes can affect how your disease will behave and which treatment will work best for you. Karyotype testing may be needed to help diagnose and treat conditions such as:
  Leukemia
  Lymphoma
  Multiple myeloma
  Anemia
For a karyotype test, the type of sample you provide depends on the reason for the test.
To test the chromosomes of an unborn baby, the sample may be gathered using:
- Amniocentesis. This procedure collects a sample of the amniotic fluid that surrounds the unborn baby during pregnancy. The fluid contains cells from the baby that can be tested. Amniocentesis is usually done between week 15 and 20 of pregnancy.
- Chorionic villus sampling (CVS). This procedure collects tissue from the chorionic villi, which are parts of the placenta that usually have the same chromosomes as the unborn baby. (The placenta is the organ that grows in the uterus to provide nutrients and oxygen to the baby.) A CVS is usually done between week 10 and 13 of pregnancy.
To test the chromosomes of adults, children, and babies, the sample may be from:
- A blood test. This is the most common sample used for karyotype tests. A health care professional will use a small needle to remove a blood sample from a vein in your arm.
- A buccal (cheek) swab. A health care professional will insert a swab into your mouth and rub it across the inside of your cheek to gather a sample of cells.
- A bone marrow test. This test may be used if you have a certain type of cancer or blood disorder. Marrow is soft, spongy tissue found inside of bones. Most bone marrow samples are taken from the back of the hip bone.
1. Karyotype Genetic Test: MedlinePlus Lab Test Information [accessed on Nov 05, 2018]
2. https://labtestsonline.org/tests/chromosome-analysis-karyotyping [accessed on Nov 05, 2018]
3. 511035: Chromosome Analysis, Whole Blood (Constitutional) | LabCorp [accessed on Oct 03, 2018]
4. Chromosome Analysis, Blood (14596) [accessed on Oct 03, 2018]

Normal reference ranges can vary depending on the laboratory and the method used for testing. You must use the range supplied by the laboratory that performed your test to evaluate whether your results are "within normal limits."

Additional Materials (1)

2:36

Chromosome Analysis - karyotyping

Pathology Tests Explained/YouTube

Reproductive Cancers

Sensitive content

This media may include sensitive content

Testicular Cancer

Image by Scientific Animations, Inc.

Male Reproductive Cancers

Reproductive cancers start in the organs related to reproduction (sex). These organs are in the pelvis. The pelvis is the area in the lower belly between the hip bones.

Male Reproductive Cancers

There are a few different types of reproductive cancers that occur in men. The most common ones are:

Testicular cancer – begins in the testes, the two egg-shaped glands that make sperm in the scrotum (ball sac) near the base of the penis
Penile cancer – begins in the penis, part of the external genitals
Prostate cancer – begins in the prostate, a gland inside the pelvis (the area in the lower belly between the hip bones) that surrounds the urethra (the tube that empties the bladder)

HPV Vaccine and Cancer Prevention

The human papillomavirus (HPV) is the most common sexually transmitted infection (STI) in the United States. There are many different types of HPV, some that are low-risk and others that are high-risk. Having high-risk strains of HPV can increase a person’s risk of certain reproductive cancers, namely cervical, vaginal and vulvar, and penile cancer.

HPV vaccines are safe and effective. They can protect males and females against diseases and health problems caused by HPV, including genital warts and some cancers.

Source: U.S. Department of Health and Human Services

Additional Materials (3)

Sensitive content

This media may include sensitive content

testicular self examination

BruceBlaus

Sensitive content

This media may include sensitive content

Male Reproductive System Showing Testicle Infected with Cancer

TheVisualMD

1:40

The male reproductive system | Cancer Research UK

Cancer Research UK/YouTube

Workplace Risks

Smoking and Erectile Dysfunction

Image by TheVisualMD

Men’s Reproductive Health in the Workplace

Though there is no complete list of reproductive hazards in the workplace, a number of workplace substances have been identified as reproductive hazards for men. Reproductive hazards are substances that affect the ability to have healthy children. Learn more about specific exposures found to have reproductive effects in men and how you can lower your exposures.

Some examples of reproductive hazards include:

Radiation
Pesticides
Various chemicals and solvents
Legal and illegal drugs
Cigarettes
Heat

Scientists are just beginning to understand how reproductive hazards affect the male reproductive system. Although more than 1,000 workplace chemicals have been shown to have reproductive effects on animals, most have not been studied in humans. There are over 72 million unique chemicals registered by the American Chemical Society, with about 15,000 new substances added every day, most of which are not tested for reproductive health effects.

Reproductive Health Problems Potentially Associated with Workplace Exposures

The Table below shows examples of reproductive hazards for men in the workplace. Although studies have found that workplace exposures may affect the reproductive system in some men, these effects do not necessarily occur in every worker. Some of the agents listed in the Table are well-known reproductive hazards (such as lead), while the scientific evidence for the others may not be as definitive.

Whether or not an exposure will cause a reproductive problem depends on:

The amount of time you’re exposed
The amount of the hazard you’re exposed to
How you were exposed.
How your body reacts to the hazard

These are only examples of hazards. Do not assume that a substance is safe if it is missing from the table.

Table – Examples of Potential Reproductive Hazards

Examples of Potential Reproductive Hazards
Reproductive problem:	Examples
Low Hormone Levels Some reproductive hazards can change the level of hormones in a man’s body. This could affect how sperm are made or the man’s sexual performance.	insecticides, lead, organophosphate, DDE, manganese, phthalates
Low Number of Sperm Some reproductive hazards can stop or slow the actual production of sperm. This means that there will be fewer sperm present to fertilize an egg; if no sperm are produced, the man is sterile.	lead, diesel exhaust, pesticide, bisphenol A, organophosphate, chromium, paraquat/malathion
Irregular Sperm Shape Reproductive hazards may cause the shape of sperm cells to be different. These sperm often have trouble swimming or are unable to fertilize the egg.	insecticides, lead, carbon disulfide, pesticides, bisphenol A, petrochemical, carbofuran, nickel
Irregular Sperm Genetics Some reproductive hazards can affect the genetics (DNA) found in sperm. The sperm and egg each contribute 23 chromosomes at fertilization. The genetic information, or DNA, stored in these chromosomes determines what we will look like and how our bodies will function. Radiation or chemicals may cause changes or breaks in the DNA. If a sperm’s DNA is damaged, it may not be able to fertilize an egg; or if it does fertilize an egg, it may affect the development of the unborn baby.	phthalates, styrene, organophosphate, carbaryl, fenvalerate, lead, benzene
Chemicals in Semen Hazardous chemicals may collect in the epididymis, seminal vesicles, or prostate. These chemicals may kill the sperm, change the way in which they swim, or attach to the sperm and be carried to the egg.	lead, trichloroethylene, boron, cadmium
Low Amount of Semen On average a man ejaculates about 3/4 of a teaspoon of semen. Some exposures may reduce this to less than 1/2 teaspoon. This may result in the fluid not transporting the sperm to the cervix (opening to the womb)	lead, organophosphate, paraquat/malathion
Low Number of Swimming Sperm Sperm have to swim through much of the woman’s reproductive tract. Slow or not swimming sperm reduces the number of sperm available for fertilization.	insecticides, diesel exhaust, lead, carbon disulfide, phthalates, pesticides, bisphenol A, fenvalerate, petrochemical, welding, N, N-dimethylformamide, abamectin, paraquat/malathion
Lower Sex Drive Some exposures may reduce the man’s sex drive or libido. This could result in not having intercourse during the women’s fertile time.	carbon disulfide, bisphenol A
Erectile Dysfunction (ED) Some exposures affect the ability for a man’s penis to be hard enough for sex.	bisphenol A, bicycle saddles
Lower Penis Sensitivity If an exposure reduces the feeling in the penis the man may not be stimulated enough to ejaculate	bicycle saddles
Lower Ejaculation Quality If an exposure limits the ejaculation process sperm cannot reach the cervix (womb opening) and cannot get to the egg.	bisphenol A

Can You Expose Your Family to Workplace Hazards?

Your family may never come to your workplace but could be exposed to hazards in your workplace that you may accidentally bring home. This could affect your partner’s health, the health of a pregnancy or your children. Many chemicals can be carried to your car or to your home on your skin, hair, clothes, shoes or tool box exposing others in the family. Some infections, including Zika virus, can be passed to sexual partners.

Source: Centers for Disease Control and Prevention (CDC)

Additional Materials (2)

Sensitive content

This media may include sensitive content

Just Socially?

TheVisualMD

13:08

Chemical Exposures and Our Health

University of California Television (UCTV)/YouTube

Share and discuss

Share your story, discuss an issue or get
advice from the community

Create conversation

Sign up here for full access to StoryMD

Get free access to in-depth articles and track your personal health.

Create Free Account Sign In