
Testing further for a form of prostate-specific antigen (PSA) can help urologists find, stage, and classify prostate cancer in men whose PSA tests are ambiguous, according to a multicenter study that included The Johns Hopkins Hospital. The additional test, which is routinely available for all men taking the PSA test, can also help patients and their doctors determine the best course of treatment. The test measures free PSA, the form of PSA not bound to proteins in the blood. According to the study, the higher the percentage of free PSA compared to the bound form, the smaller the tumor is likely to be, the less chance there is that it has spread from the prostate, and the less likely it is that the disease is the most aggressive form.











































































