Prostate-Specific Antigen (PSA), Free: Total Ratio

Prostate-specific antigen (PSA) is a protein that is produced by the prostate gland. Higher levels of PSA can sometimes be an indicator of prostate cancer. This blood test is used to aid in diagnosing and in monitoring treatment of prostate cancer.

Other noncancerous conditions that can caused elevated PSA levels are inflammation of the prostate and enlargement of the prostate.

In men over 50 years with total PSA between 4.0 and 10.0 ng/mL, the percent of free PSA gives an estimate of the probability of cancer. In these circumstances the measurement of the percent of free PSA may aid in avoiding unnecessary biopsies.
Elevated levels of PSA have been associated with benign and malignant prostatic disorders. Studies indicate that in men 50 years or older measurement of PSA is a useful addition to the digital rectal exam in the early detection of prostate cancer. In addition, PSA decreases to undetectable levels following complete resection of the tumor and may rise again with recurrent disease or persist with residual disease. Thus, PSA levels may be of assistance in the management of prostate cancer patients.