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More about Prostate-Specific Antigen Test:
Purpose Precautions Preparation Normal results Abnormal results Resources |
Definition
Prostate-specific antigen, or PSA, is a protein produced by the prostate gland that may be found in elevated levels in the blood when a person develops certain diseases of the prostate, notably prostate cancer. PSA is specific, because it is present only in prostate tissue. It is not specific for prostate cancer, however, as it may also be elevated in men with benign enlargement of this organ. The PSA test has been called the "male PAP test."
Description
The PSA test is a radioimmunoassay. Any antigen causes the body to produce antibodies in an attempt to neutralize or eliminate the antigen, often a substance that harms body tissues. In the laboratory, a sample of the patient's blood is exposed to the antibody against PSA, so that the amount of antigen (PSA) can be measured. The results generally are available the next day.
— David A. Cramer, MD
