What is a prostate-specific antigen (PSA) test?
A prostate-specific antigen (PSA) test measures the level of PSA in your blood. The prostate is a small gland that is part of a man’s reproductive system. It is located below the bladder and makes a fluid that is part of semen. PSA is a substance made by the prostate. Men normally have low PSA levels in their blood. A high PSA level may be a sign of prostate cancer, the most common non-skin cancer affecting American men. But high PSA levels can also mean noncancerous prostate conditions, such as infection or benign prostatic hyperplasia, a noncancerous enlargement of the prostate.
Other names: total PSA, free PSA
What is it used for?
A PSA test is used to screen for prostate cancer. Screening is a test that looks for a disease, such as cancer, in its early stages, when it’s most treatable. Leading health organizations, such as the American Cancer Society and the Centers for Disease Control and Prevention (CDC), disagree on recommendations for using the PSA test for cancer screening. Reasons for disagreement include:
- Most types of prostate cancer grow very slowly. It can take decades before any symptoms show up.
- Treatment of slow-growing prostate cancer is often unnecessary. Many men with the disease live long, healthy lives without ever knowing they had cancer.
- Treatment can cause major side effects, including erectile dysfunction and urinary incontinence.
- Fast-growing prostate cancer is less common, but more serious and often life-threatening. Age, family history, and other factors can put you at higher risk. But the PSA test alone can’t tell the difference between slow- and fast-growing prostate cancer.