Categories of some common laboratory tests used in cancer medicine are listed below in alphabetical order.
Blood chemistry test
What it measures: The amounts of certain substances that are released into the blood by the organs and tissues of the body, such as metabolites, electrolytes, fats, and proteins, including enzymes. Blood chemistry tests usually include tests for blood urea nitrogen (BUN) and creatinine.
How it is used: Diagnosis and monitoring of patients during and after treatment. High or low levels of some substances can be signs of disease or side effects of treatment.
Cancer gene mutation testing
What it measures: The presence or absence of specific inherited mutations in genes that are known to play a role in cancer development. Examples include tests to look for BRCA1 and BRCA2 gene mutations, which play a role in development of breast, ovarian, and other cancers.
How it is used: Assessment of cancer risk
Complete blood count (CBC)
What it measures: Numbers of the different types of blood cells, including red blood cells, white blood cells, and platelets, in a sample of blood. This test also measures the amount of hemoglobin (the protein that carries oxygen) in the blood, the percentage of the total blood volume that is taken up by red blood cells (hematocrit), the size of the red blood cells, and the amount of hemoglobin in red blood cells.
How it is used: Diagnosis, particularly in leukemias, and monitoring during and after treatment
Cytogenetic analysis
What it measures: Changes in the number and/or structure of chromosomes in a patient’s white blood cells or bone marrow cells
How it is used: Diagnosis, deciding on appropriate treatment
Immunophenotyping
What it measures: Identifies cells based on the types of antigens present on the cell surface
How it is used: Diagnosis, staging, and monitoring of cancers of the blood system and other hematologic disorders, including leukemias, lymphomas, myelodysplastic syndromes, and myeloproliferative disorders. It is most often done on blood or bone marrow samples, but it may also be done on other bodily fluids or biopsy tissue samples.
Sputum cytology (also called sputum culture)
What it measures: The presence of abnormal cells in sputum (mucus and other matter brought up from the lungs by coughing)
How it is used: Diagnosis of lung cancer
Tumor marker tests
What they measure: Some measure the presence, levels, or activity of specific proteins or genes in tissue, blood, or other bodily fluids that may be signs of cancer or certain benign (noncancerous) conditions. A tumor that has a greater than normal level of a tumor marker may respond to treatment with a drug that targets that marker. For example, cancer cells that have high levels of the HER2/neu gene or protein may respond to treatment with a drug that targets the HER2/neu protein.
Some tumor marker tests analyze DNA to look for specific gene mutations that may be present in cancers but not normal tissues. Examples include EGFR gene mutation analysis to help determine treatment and assess prognosis in non-small cell lung cancer and BRAF gene mutation analysis to predict response to targeted therapies in melanoma and colorectal cancer.
Still other tumor marker tests, called multigene tests (or multiparameter gene expression tests), analyze the expression of a specific group of genes in tumor samples. These tests are used for prognosis and treatment planning. For example, the 21-gene signature can help patients with lymph node–negative, estrogen receptor–positive breast cancer decide if there may be benefit to treating with chemotherapy in addition to hormone therapy, or not.
How they are used: Diagnosis, deciding on appropriate treatment, assessing response to treatment, and monitoring for cancer recurrence
Urinalysis
What it measures: The color of urine and its contents, such as sugar, protein, red blood cells, and white blood cells.
How it is used: Detection and diagnosis of kidney cancer and urothelial cancers
Urine cytology
What it measures: The presence of abnormal cells shed from the urinary tract into urine to detect disease.
How it is used: Detection and diagnosis of bladder cancer and other urothelial cancers, monitoring patients for cancer recurrence