What should I know about protein-specific antigen (PSA) testing?

Marc B. Garnick, MD
Hematology & Oncology
A prostate-specific antigen (PSA) test is a blood test that measures the level of a protein called PSA, which is made by cells in the prostate. Elevated PSA levels may indicate the presence of cancer, benign prostatic hyperplasia (BPH) -- enlarged prostate, or prostatitis -- inflammation or infection of the prostate.

Here's what you should know about PSA screening:
  • Screening doesn't lower your risk of having prostate cancer; it increases the chance you'll find out you have it.
  • PSA testing can detect early-stage cancers that a digital rectal examination (DRE) would miss.
  • A "normal" PSA level of 4 nanograms per milliliter (ng/mL) or below doesn't guarantee that you are cancer-free; in about 15% of men with a PSA below 4 ng/mL, a biopsy will reveal prostate cancer.
Although a level of 4 was initially thought to be the upper limit of normal value, there is really no specific value that provides a level of certainty that a patient does  or does not have prostate cancer. Cancer can be found in men with extremely low PSA values.
  • A high PSA level may prompt you to seek treatment - Conditions other than cancer, such as benign prostatic hyperplasia (BPH) or inflammation of the prostate (prostatitis), or activities such as bike riding and sex can elevate the PSA level.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.