[Determination of free PSA in 85 consecutive cases with increased total PSA]

With a view to a more clearcut discrimination between benign prostatic hyperplasia (BPH) and prostate cancer (PCA), an additional measurement of the free PSA serum concentration and its ratio to total PSA (f-PSA/t-PSA) were determined in sera from 85 consecutive ambulatory patients with a total PSA concentration exceeding 4 ng/ml. Results with a ratio higher than 0.16 correlated with a high probability of benign disease (BPH), while a ratio below 0.16 was less meaningful. Thus, testing of free PSA seems to contribute to reducing the number of unnecessary biopsies in patients with elevated PSA.