Free and total prostate specific antigen (F-PSA and T-PSA) in serum were measured with immunoradiometritic assay and the F/T-PSA ratio was calculated in 175 patients with T-PSA levels in the range of 4-20 μg/L. Among them 141 patients were benign prostatic hyperplasia (BPH), 23 were untreated prostate cancer (Pca untreated) and 11 were treated prostate cancer (Pca treated). The results showed that difference in F-PSA and F/T-PSA ratio for BPH group and Pca untreated group were statistically significant (P<0...