Prostate-specific antigen (PSA) is a substance released into a man's blood by his prostate gland. A PSA test measures the amount of prostate-specific antigen in the blood.
Low amounts of PSA may be found in the blood of healthy men. The amount of PSA in the blood normally increases as a man's prostate enlarges with age. It is also increased by inflammation of the prostate gland (prostatitis) and by prostate cancer.
Last Revised: June 21, 2010
Author: Healthwise Staff
Medical Review: E. Gregory Thompson, MD - Internal Medicine & J. Curtis Nickel, MD, FRCSC - Urology
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