Prostate-Specific Antigen

Prostate-specific antigen (PSA) is an enzyme produced by the prostate gland. Normally, PSA is secreted in small amounts into the bloodstream. However, larger amounts of PSA are released when the prostate gland is enlarged, infected, or diseased. The level of PSA in the blood can be determined by a simple blood test. Its measurement is done exclusively to help detect prostate cancer. PSA testing has dramatically increased the number of men diagnosed with prostate cancer to approximately 300,000 per year. While PSA has revolutionized the detection of prostate cancer, it is not a perfect test. False positives and false negatives may occur.

The use of PSA should ideally be combined with a physical exam to help detect prostate cancer. According to the American Cancer Society, men aged 50 and older, and those over the age of 45 who are in high-risk groups, such as African-American men and men with a family history of prostate cancer, should have a prostate-specific antigen (PSA) blood test and digital rectal exam (DRE) once every year.