What is a PSA blood test?
Prostate specific antigen (PSA) test is the most important test in prostate cancer diagnosis and follow-up. Prostate cancer and certain other conditions can cause an increase in the PSA value. If the PSA value is higher than 4.0 nanograms per milliliter (ng/mL) in a normal middle-aged male, the doctor would consider further testing to see whether prostate cancer could be the cause. For more information, see the diagnosis of prostate cancer.
A. The PSA blood test is an important tool in helping to detect prostate cancer, especially when it is done along with a digital rectal examination (DRE). Often, the doctor will order blood tests to measure a substance called prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP). The level of PSA in the blood may rise in men who have prostate cancer or benign prostatic hypertrophy. The level of PAP rises above normal in many prostate cancer patients, especially if the cancer has spread beyond the prostate. The doctor cannot diagnose prostate cancer with these tests alone. However, the doctor will take the results of the tests into account when deciding whether to check the patient further for signs of cancer.
