Prostate-specific Antigen (PSA) Blood Test Free:Total Ratio (Serial Monitor) - NOT CURRENTLY AVAILABLE

Most PSA tests measure "total PSA," or the amount that is bound to blood proteins. In March, FDA approved the Tandem R test, which measures not only total PSA but another component called "free PSA," which floats unbound in the blood. Comparing the two helps doctors rule out cancer in men whose PSA is mildly elevated from other causes. A 1995 study in the Journal of the American Medical Association showed that the free PSA test can reduce unnecessary prostate biopsies by 20 percent in patients with a PSA between 4 and 10.