Prostate-specific antigen (PSA) is a protein produced by cells in the prostate gland. The PSA laboratory test measures the level of that protein in a man’s blood.
PSA readings are reported as nanograms of PSA per milliliter of blood (ng/mL) Older men typically have higher PSA readings than younger ones, according to the National Cancer Institute.
Normal values for a PSA test vary from one lab to the next. Historically, readings over 4 ng/mL were considered abnormally high, but the National Cancer Institute states as of March 2009 there is no generally accepted normal or abnormal PSA level.
While it’s normal for men to have low PSA levels, an elevated PSA may indicate prostate cancer. However, prostatitis (inflammation of the prostate gland) or benign prostatic hyperplasia (enlargement of the prostate) can also raise PSA levels.
The National Cancer Institute recommends that a man discuss his PSA result with his doctor to determine if the level is high enough to warrant concern.
An elevated PSA level, along with an abnormal digital rectal exam, can help identify prostate cancer in its early stages. With early detection and prompt treatment, almost 100 percent of men diagnosed with prostate cancer are cancer-free five years later.