PSA is used to screen for prostate cancer. Learn more about PSA.

By Mayo Clinic Staff

Prostate-specific antigen (PSA) is a protein in a man's body that is sometimes used to screen for prostate cancer.

PSA is a protein produced by both cancerous (malignant) and noncancerous (benign) prostate tissue.

PSA helps liquefy the semen. A small amount of PSA normally enters the bloodstream.

In men with cancer, prostate cancer cells usually make more PSA than do benign cells. This causes PSA levels in the blood to rise.

But PSA levels can also be elevated in men who don't have prostate cancer. Conditions that could lead to an elevated PSA level in men who don't have prostate cancer include:

  • Benign prostate enlargement (benign prostatic hyperplasia)
  • A prostate infection (prostatitis)
  • Other less common conditions
Mar. 22, 2014