Free/Total PSA Ratio

Short Name: PSA/RA
Sample required: Serum
Result Time: 2 HR

This ratio is determined by dividing the amount of PSA that circulates freely in the blood stream by the amount of PSA that is bound to proteins in the blood stream. PSA that circulates freely in the blood tends to be associated with benign prostatic hypertrophy (BPH) whereas the PSA that is bound to protein tends to be linked with prostate cancer. Thus, a high PSA ratio suggests a false-positive elevation of the PSA and weighs against the diagnosis of prostate cancer. In contrast, a high PSA with a low PSA ratio favors the diagnosis of prostate cancer.