Prostate-specific antigen (PSA) is a protein made by the prostate gland. The prostate is a walnut-sized gland in men, located near the bladder and rectum. It produces a fluid that is part of semen. Most PSA is released into semen, but some is released into the bloodstream. If there is a problem with the prostate, the PSA found in the blood can become elevated.

Anatomy of the Prostate
Anatomy of the Prostate Gland
© 2011 Nucleus Medical Media, Inc.

The PSA test is used to:

  • Screen for prostate cancer
  • Monitor treatment for prostate cancer
  • Help determine if cancer has returned in men who have already been treated for prostate cancer

An elevated PSA level may also be associated with prostatitis (inflammation of the prostate) and an enlarged prostate ( benign prostatic hyperplasia).