What is a PSA test?
A prostate-specific antigen (PSA) test measures the level of PSA in the blood. The prostate gland produces PSA, a protein that at an elevated level may be a sign of prostate cancer. A high PSA reading also may indicate noncancerous conditions such as inflammation of the prostate (prostatitis) and enlargement of the prostate (benign prostatic hyperplasia).
Men who have symptoms associated with prostate cancer may have a PSA test along with a digital rectum exam (DRE). These symptoms include burning or pain during urination, loss of bladder control, painful ejaculation, and swelling in legs or pelvic area. For the test, a clinician takes a sample of your blood and sends it to a lab for analysis.
PSA levels are measured in nanograms of PSA per milliliter of blood, or ng/mL. Men with a high PSA level are more likely to have prostate cancer than men with low levels, though there are no normal and abnormal ranges of PSA in the blood.
In the past, a PSA reading of 4 ng/mL and below was considered normal. Men with a reading above 4 ng/mL were considered likely to have prostate cancer and would have a biopsy to confirm the cancer’s presence. According to the National Cancer Institute, research has found that men with prostate cancer can have a low PSA level, while men without prostate cancer can have a high level. One in four men with an elevated PSA level actually has prostate cancer. However, an increase in PSA level over time may indicate prostate cancer.
Men with a high PSA level may be monitored under active surveillance, which involves PSA testing at regular intervals. Learn more about active surveillance.
PSA test for prostate cancer
The PSA test is one of the earliest ways to detect prostate cancer. It is often done along with a DRE so your doctor can feel the prostate for any abnormalities in shape, size and texture. A high PSA level may be a sign of prostate cancer but it also can be due to a urinary tract infection or prostatitis and benign prostatic hyperplasia, both of which are noncancerous conditions.