A blood transfusion is a common, safe medical procedure in which healthy blood is given to you through an intravenous (IV) line that has been inserted in one of your blood vessels.

Overview

Your blood carries oxygen and nutrients to all parts of your body. Blood transfusions replace blood that is lost through surgery or injury or provide it if your body is not making blood properly. You may need a blood transfusion if you have anemia, sickle cell disease, a bleeding disorder such as hemophilia, or cancer. For people in critical condition, blood transfusions can be lifesaving.

Four types of blood products may be given through blood transfusions: whole blood, red blood cells, platelets, and plasma. Most of the blood used for transfusions comes from whole blood donations given by volunteer blood donors. A person can also have his or her own blood collected and stored a few weeks before surgery in case it is needed.

After a doctor determines that you need a blood transfusion, he or she will test your blood to make sure that the blood you are given matches your blood type. A small needle is used to insert an IV line in one of your blood vessels. Through this line, you receive healthy blood. Blood transfusions usually take 1 to 4 hours to complete. You will be monitored during and after the procedure.

Blood transfusions are usually very safe, because donated blood is carefully tested, handled, and stored. However, there is a small chance that your body may have a mild to severe reaction to the donor blood. Other complications may include fever, heart or lung complications, alloimmunization, and rare but serious reactions in which donated white blood cells attack your body’s healthy tissues. Some people have health problems from getting too much iron from frequent transfusions. There is also a very small chance of getting an infectious disease such as hepatitis B or C or HIV through a blood transfusion. For HIV, that risk is less than one in 1 million. Scientific research and careful medical controls make the supply of donated blood very safe. Blood transfusions are among the most common medical procedures in the nation.

Blood is transfused either as whole blood (with all its parts) or, more often, as individual parts. The type of blood transfusion you need depends on your situation.

For example, if you have an illness that stops your body from properly making a part of your blood, you may need only that part to treat the illness.

Red Blood Cell Transfusions

Red blood cells are the most commonly transfused part of the blood. These cells carry oxygen from the lungs to your body's organs and tissues. They also help your body get rid of carbon dioxide and other waste products.

You may need a transfusion of red blood cells if you've lost blood due to an injury or surgery. You also may need this type of transfusion if you have severe(uh-NEE-me-uh) due to disease or blood loss.

Anemia is a condition in which your blood has a lower than normal number of red blood cells. Anemia also can occur if your red blood cells don't have enough hemoglobin (HEE-muh-glow-bin).

Hemoglobin is an iron-rich protein that gives blood its red color. This protein carries oxygen from the lungs to the rest of the body.

Platelets and Clotting Factor Transfusions

Platelets and clotting factors help stop bleeding, including internal bleeding that you can't see. Some illnesses may cause your body to not make enough platelets or clotting factors. You may need regular transfusions of these parts of your blood to stay healthy.

For example, if you have hemophilia (heem-o-FILL-ee-ah), you may need a special clotting factor to replace the clotting factor you're lacking. Hemophilia is a rare, inherited bleeding disorder in which your blood doesn't clot normally.

If you have hemophilia, you may bleed for a longer time than others after an injury or accident. You also may bleed internally, especially in the joints (knees, ankles, and elbows).

Plasma Transfusions

Plasma is the liquid part of your blood. It's mainly water, but also contains proteins, clotting factors, hormones, vitamins, cholesterol, sugar, sodium, potassium, calcium, and more.

If you have been badly burned or have liver failure or a severe infection, you may need a plasma transfusion.

Blood transfusions are very common. Each year, almost 5 million Americans need blood transfusions. This procedure is used for people of all ages.

Many people who have surgery need blood transfusions because they lose blood during their operations. For example, about one-third of all heart surgery patients have a transfusion.

Some people who have serious injuries-such as from car crashes, war, or natural disasters-need blood transfusions to replace blood lost during the injury.

Some people need blood or parts of blood because of illnesses. You may need a blood transfusion if you have:

• A severe infection or liver disease that stops your body from properly making blood or some parts of blood.
• An illness that causes anemia, such as kidney disease or cancer. Medicines or radiation used to treat a medical condition also can cause anemia. There are many types of anemia, including aplastic, Fanconi, hemolytic, iron-deficiency, and sickle cell anemias and thalassemia (thal-ah-SE-me-ah).
• A bleeding disorder, such as hemophilia or thrombocytopenia (THROM-bo-si-to-PE-ne-ah).

What To Expect Before

Before a blood transfusion, a technician tests your blood to find out what blood type you have (that is, A, B, AB, or O and Rh-positive or Rh-negative). He or she pricks your finger with a needle to get a few drops of blood or draws blood from one of your veins.

The blood type used in your transfusion must work with your blood type. If it doesn't, antibodies (proteins) in your blood attack the new blood and make you sick.

Some people have allergic reactions even when the blood given does work with their own blood type. To prevent this, your doctor may prescribe a medicine to stop allergic reactions. If you have allergies or have had an allergic reaction during a past transfusion, your doctor will make every effort to make sure you're safe.

Most people don't need to change their diets or activities before or after a blood transfusion. Your doctor will let you know whether you need to make any lifestyle changes prior to the procedure.

What To Expect During

Blood transfusions take place in either a doctor's office or a hospital. Sometimes they're done at a person's home, but this is less common. Blood transfusions also are done during surgery and in emergency rooms.

A needle is used to insert an intravenous (IV) line into one of your blood vessels. Through this line, you receive healthy blood. The procedure usually takes 1 to 4 hours. The time depends on how much blood you need and what part of the blood you receive.

During the blood transfusion, a nurse carefully watches you, especially for the first 15 minutes. This is when allergic reactions are most likely to occur. The nurse continues to watch you during the rest of the procedure as well.

What To Expect After

After a blood transfusion, your vital signs are checked (such as your temperature, blood pressure, and heart rate). The intravenous (IV) line is taken out. You may have some bruising or soreness for a few days at the site where the IV was inserted.

You may need blood tests that show how your body is reacting to the transfusion. Your doctor will let you know about signs and symptoms to watch for and report.

Most blood transfusions go very smoothly. However, mild problems and, very rarely, serious problems can occur.

Allergic Reactions

Some people have allergic reactions to the blood given during transfusions. This can happen even when the blood given is the right blood type.

Allergic reactions can be mild or severe. Symptoms can include:

• Anxiety
• Chest and/or back pain
• Trouble breathing
• Fever, chills, flushing, and clammy skin
• A quick pulse or low blood pressure
• Nausea (feeling sick to the stomach)

A nurse or doctor will stop the transfusion at the first signs of an allergic reaction. The health care team determines how mild or severe the reaction is, what treatments are needed, and whether the transfusion can safely be restarted.

Viruses and Infectious Diseases

Some infectious agents, such as HIV, can survive in blood and infect the person receiving the blood transfusion. To keep blood safe, blood banks carefully screen donated blood.

The risk of catching a virus from a blood transfusion is very low.

• HIV. Your risk of getting HIV from a blood transfusion is lower than your risk of getting killed by lightning. Only about 1 in 2 million donations might carry HIV and transmit HIV if given to a patient.
• Hepatitis B and C. The risk of having a donation that carries hepatitis B is about 1 in 205,000. The risk for hepatitis C is 1 in 2 million. If you receive blood during a transfusion that contains hepatitis, you'll likely develop the virus.
• Variant Creutzfeldt-Jakob disease (vCJD). This disease is the human version of Mad Cow Disease. It's a very rare, yet fatal brain disorder. There is a possible risk of getting vCJD from a blood transfusion, although the risk is very low. Because of this, people who may have been exposed to vCJD aren't eligible blood donors.

Fever

You may get a sudden fever during or within a day of your blood transfusion. This is usually your body's normal response to white blood cells in the donated blood. Over-the-counter fever medicine usually will treat the fever.

Some blood banks remove white blood cells from whole blood or different parts of the blood. This makes it less likely that you will have a reaction after the transfusion.

Iron Overload

Getting many blood transfusions can cause too much iron to build up in your blood (iron overload). People who have a blood disorder like thalassemia, which requires multiple transfusions, are at risk for iron overload. Iron overload can damage your liver, heart, and other parts of your body.

If you have iron overload, you may need iron chelation (ke-LAY-shun) therapy. For this therapy, medicine is given through an injection or as a pill to remove the extra iron from your body.

Lung Injury

Although it's unlikely, blood transfusions can damage your lungs, making it hard to breathe. This usually occurs within about 6 hours of the procedure.

Most patients recover. However, 5 to 25 percent of patients who develop lung injuries die from the injuries. These people usually were very ill before the transfusion.

Doctors aren't completely sure why blood transfusions damage the lungs. Antibodies (proteins) that are more likely to be found in the plasma of women who have been pregnant may disrupt the normal way that lung cells work. Because of this risk, hospitals are starting to use men's and women's plasma differently.

Acute Immune Hemolytic Reaction

Acute immune hemolytic reaction is very serious, but also very rare. It occurs if the blood type you get during a transfusion doesn't match or work with your blood type. Your body attacks the new red blood cells, which then produce substances that harm your kidneys.

The symptoms include chills, fever, nausea, pain in the chest or back, and dark urine. The doctor will stop the transfusion at the first sign of this reaction.

Delayed Hemolytic Reaction

This is a much slower version of acute immune hemolytic reaction. Your body destroys red blood cells so slowly that the problem can go unnoticed until your red blood cell level is very low.

Both acute and delayed hemolytic reactions are most common in patients who have had a previous transfusion.

Graft-Versus-Host Disease

Graft-versus-host disease (GVHD) is a condition in which white blood cells in the new blood attack your tissues. GVHD usually is fatal. People who have weakened immune systems are the most likely to get GVHD.

Symptoms start within a month of the blood transfusion. They include fever, rash, and diarrhea. To protect against GVHD, people who have weakened immune systems should receive blood that has been treated so the white blood cells can't cause GVHD.

Keeping the United States blood supply the world's safest is the ultimate responsibility of the nation's blood establishments that collect and process the units of whole blood donated by volunteers each year. The Food and Drug Administration, however, has the vital role of ensuring that patients who receive a blood transfusion are protected by multiple overlapping safeguards. This FDA blood-safety system includes measures in the following areas:

• Donor screening
• Blood testing
• Donor deferral lists
• Quarantine
• Problems and Deficiencies

Donor screening: Donor screening plays an important role in ensuring the safety of the U.S. blood supply. FDA regulations require that a donor be free from any disease transmissible by blood transfusion, in so far as can be determined by health history and examination.

Donors are informed about potential risks and are required to answer questions about factors that may have a bearing on the safety of their blood. For example, donors with a history of intravenous drug abuse are routinely deferred.

In addition to federal regulations, FDA periodically issues guidance documents providing recommendations to decrease the potential for transmission of infectious diseases when new information or testing methodologies becomes available. For example, since November 1999, the FDA has recommended that the blood industry defer potential donors who have lived in the United Kingdom and other European countries to reduce the risk of variant Creutzfeldt-Jakob disease (vCJD), the human form of "mad cow disease."

Blood testing: The FDA reviews and approves all test kits used to detect infectious diseases in donated blood. After donation, each unit of donated blood is required to undergo a series of tests for infectious diseases, including:

• Hepatitis B and C viruses
• Human Immunodeficiency Virus, Types 1 and 2
• Human T-Lymphotropic Virus, Types I and II
• Treponema pallidum (Syphilis)

Additionally, FDA recommends testing for the following infectious diseases:

• West Nile Virus
• Trypanosoma cruzi (Chagas disease)

Donor deferral lists: Blood establishments must keep current a list of deferred donors and use it to make sure that they do not collect blood from anyone on the list.

Quarantine: Donated blood must be quarantined until it is tested and shown to be free of infectious agents.

Problems and deficiencies: Blood centers must investigate manufacturing problems, correct all deficiencies, and notify the FDA when product deviations occur in distributed products.

If any one of these safeguards is breached, the blood component is considered unsuitable for transfusion and is subject to recall.

CDC is one of the federal agencies responsible for assuring the safety of the U.S. blood supply by protecting health through investigations and surveillance. The U.S. Food and Drug Administration (FDA) is responsible for ensuring safety of blood donations and protecting the health of the donors. Research on blood transfusion basic science, epidemiology, and clinical practices is carried out by the National Institutes of Health (NIH). Keeping the U.S. blood supply safe is also the responsibility of the blood centers and hospitals that collect and transfuse millions of units of blood each year.

Key Facts

• Each day life-saving blood transfusions are needed in hospitals and emergency treatment facilities across the U.S.
• There are more than 13.2 million blood donors in the United States, resulting in a total of 17.2 million transfused blood product units per year. (Source: Continued decline in blood collection and transfusion in the United States–2015)
• Most patients do not experience any side effects from blood transfusions. On rare occasions, blood transfusions can cause adverse reactions in the patients receiving blood.
• Although the U.S. blood supply is safer than ever before, some bacteria, viruses, prions, and parasites can be transmitted by blood transfusions.
• Each donor is screened for risk of transmissible disease by questionnaire, and each unit of blood donated in the U.S. is routinely screened for various infectious disease pathogens using FDA approved assays.

Screening Donated Blood

Blood donors are asked a set of standard questions prior to donating blood to assist in determining if they are in good health and free of any diseases that could be transmitted by blood transfusion. If the donor’s answers indicate they are not well or are at risk for having a disease transmissible by blood transfusion, they are not allowed to donate blood.

If the donor is eligible to donate, the donated blood is tested for blood type (ABO group) and Rh type (positive or negative). This is to make sure that patients receive blood that matches their blood type. Before transfusion, the donor and blood unit are also tested for certain proteins (antibodies) that may cause adverse reactions in a person receiving a blood transfusion.

All blood for transfusion is tested for evidence of certain infectious disease pathogens, such as hepatitis B and C viruses and human immunodeficiency virus (HIV). The tests used to screen donated blood are listed below.

Table: Tests Used to Screen Donated Blood

Adverse Reactions Associated with Blood Transfusions

The chance of having a reaction to a blood transfusion is very small. The most common adverse reactions from blood transfusions are allergic and febrile reactions, which make up over half of all adverse reactions reported. Rare but serious adverse reactions include infection caused by bacterial contamination of blood products and immune reactions due to problems in blood type matching between donor and recipient.

The following is a list of blood transfusion-associated adverse reactions that are tracked through the National Healthcare Safety Network (NHSN) Blood Safety Surveillance / Hemovigilance Module.

Allergic reaction

An allergic reaction results from an interaction of an allergen in the transfused blood with preformed antibodies in the person receiving the blood transfusion. In some instances, infusion of antibodies from the donor may be involved. The reaction may present only with irritation of the skin or mucous membranes but can also involve serious symptoms such as difficulty breathing.

Acute hemolytic transfusion reaction (AHTR)

An acute hemolytic transfusion reaction is the rapid destruction of red blood cells that occurs during, immediately after, or within 24 hours of a transfusion when a patient is given an incompatible blood type. The recipient’s body immediately begins to destroy the donated red blood cells resulting in fever, pain, and sometimes severe complications such as kidney failure.

Delayed hemolytic transfusion reaction (DHTR)

A delayed hemolytic transfusion reaction occurs when the recipient develops antibodies to red blood cell antigens between 24 hours and 28 days after a transfusion. Symptoms are usually milder than in acute hemolytic transfusion reactions and may even be absent. DHTR is diagnosed with laboratory testing.

Delayed serologic transfusion reaction (DSTR)

A delayed serologic transfusion reaction occurs when a recipient develops new antibodies against red blood cells between 24 hours and 28 days after a transfusion without clinical symptoms or laboratory evidence of hemolysis. Clinical symptoms are rarely associated with DSTR.

Febrile non-hemolytic transfusion reaction (FNHTR)

Febrile non-hemolytic transfusion reactions are the most common reaction reported after a transfusion. FNHTR is characterized by fever or chills in the absence of hemolysis (breakdown of red blood cells) occurring in the patient during or up to 4 hours after a transfusion. These reactions are generally mild and respond quickly to treatment. Fever can be a symptom of a more severe reaction with more serious causes, and should be fully investigated.

Hypotensive transfusion reaction

A hypotensive transfusion reaction is a drop in systolic blood pressure occurring soon after a transfusion begins that responds quickly to cessation of the transfusion and supportive treatment. Hypotension also can be a symptom of a more severe reaction and should be fully investigated.

Post-transfusion purpura (PTP)

Post-transfusion purpura is a rare but potentially fatal condition that occurs when a transfusion recipient develops antibodies against platelets, resulting in rapid destruction of both transfused and the patient’s own platelets and a severe decline in the platelet count. PTP usually occurs 5-12 days after a transfusion and is more common in women than in men.

Transfusion-associated circulatory overload (TACO)

Transfusion-associated circulatory overload occurs when the volume of blood or blood components are transfused cannot be effectively processed by the recipient. TACO can occur due to an excessively high infusion rate or volume or due to an underlying heart or kidney condition. Symptoms may include difficulty breathing, cough, and fluid in the lungs.

Transfusion-related acute lung injury (TRALI)

Transfusion-related acute lung injury is a serious but rare reaction that occurs when fluid builds up in the lungs, but is not related to excessive volume of blood or blood products transfused. Symptoms include acute respiratory distress with no other explanation for lung injury such as pneumonia or trauma occurring within 6 hours of transfusion. The mechanism of TRALI is not well understood, but is thought to be associated with the presence of antibodies in donor blood.

Transfusion-associated dyspnea (TAD)

Transfusion associated dyspnea is the onset of respiratory distress within 24 hours of transfusion that cannot be defined as TACO, TRALI, or an allergic reaction.

Transfusion-associated graft vs. host disease (TAGVHD)

Transfusion-associated graft vs. host disease is a rare complication of transfusion that occurs when donor T-lymphocytes (the “graft”) introduced by the blood transfusion rapidly increase in number in the recipient (the “host”) and then attack the recipient’s own cells. Symptoms include fever, a characteristic rash, enlargement of the liver, and diarrhea that occur between 2 days and 6 weeks post transfusion. Though very rare, this inflammatory response is difficult to treat and often results in death.

Transfusion-transmitted infection (TTI)

A transfusion-transmitted infection occurs when a bacterium, parasite, virus, or other potential pathogen is transmitted in donated blood to the transfusion recipient.