The prostate gland produces a substance called prostate-specific antigen, or PSA. With a simple blood test, a doctor can determine whether a man's PSA is normal or elevated. There is no definitive normal PSA level; however, guidelines are in place that help doctors decide whether or not to conduct further tests.
For most men who are healthy, doctors consider the normal PSA level to be under 4 nanograms per milliliter (ng/mL), but there is no specific normal level.
Most doctors consider a PSA level above 4 ng/mL to be an elevated reading. A man who has an elevated PSA level should talk to his doctor about what other tests might be appropriate.
Causes for Elevated PSA
Since the PSA can indicate diseases in the body, doctors refer to it as a biological marker or a tumor marker. The causes for an elevated PSA level can include prostate cancer, benign prostate enlargement, inflammation, infection, age or race.
PSA False Positives
The PSA blood test can reveal elevated PSA levels, even when no cancer is present. The National Cancer Institute reports that only 25 to 35 percent of the men who had a biopsy following an elevated PSA level had prostate cancer.
PSA False Negatives
It is possible for a man to get a normal reading in a PSA blood test and still have cancer present in the body. Prostate cancer usually grows slowly and can exist for some time before symptoms are evident.
Prostate cancer screening is recommended by the American Urological Society, the American Cancer Society and the American College of Physicians for men over the age of 50. For men who are considered to be at high risk (black men or men with a family history of prostate cancer), it is recommended that testing start between the ages of 40 to 45.