REFERENCE RANGES FOR THE CONCENTRATIONS OF TOTAL AND COMPLEXED PLASMAPROSTATE-SPECIFIC ANTIGEN AND THEIR RATIO IN PATIENTS WITH BENIGN PROSTATE HYPERPLASIA

Objective: To establish the normal distribution and reference ranges o f complexed and total prostate-specific antigen (PSA) and the complexe d-to-to-tal PSA ratio according to the age of the patients, so that PS A can be used to distinguish between prostate cancer and benign prosta te hyperplasia (BPH). Material and Methods: Using specific ELISAs, tot al PSA and PSA complexed to alpha(1)-antichymotrypsin (complexed PSA) were determined in 237 BPH patients, 160 with histologically confirmed BPH and 77 in whom prostate cancer was excluded by digital rectal exa mination, transrectal ultrasound and total PSA measurement, Results: B oth total and complexed PSA correlated with patient age (r = 0.424 and r = 0.379, p < 0.0001, respectively). However, no correlation was fou nd between the complexed-to-total PSA ratio and age (r = 0.026, p > 0. 2). The mean complexed-ta-total PSA ratio for the 237 BPH patients was 0.69 +/- 0.11, and only 23 had a ratio >0.8, Conclusions: These resul ts show that the cut-off point of 0.8 established for the complexed-to -total PSA ratio is the same for men of all ages, and that the use of this ratio may avoid many negative prostate biopsies, confirming that PSA:alpha(1)ACT is a potential marker for differential diagnosis of pr ostate carcinoma and BPH.