The normal level of prostate-specific antigen, or PSA, is 4.0 nanograms per milliliter or lower. When a PSA test gives a higher result than this number, doctors can recommend a biopsy to confirm if prostate cancer is present. This is due to the fact that many men may have an elevated level of PSA and not have cancer, while some men with a level in the normal range may have cancer, states the National Cancer Institute.
Although the PSA test can be useful in the early detection of prostate cancer, it cannot be used solely as an indication of cancer without taking into consideration certain factors and exceptions. For example, factors that can raise a man's PSA levels are age and medical conditions, such as prostatitis, benign prostatic hyperplasia and a urinary tract infection, notes the National Cancer Institute.
The PSA blood test measures the amount of PSA, which is a protein produced by the prostate gland. The digital rectal exam is another test that doctors can perform to check for abnormalities that may indicate prostate cancer, states the University of California- San Francisco Medical Center.