Serum prostate-specific antigen to predict the presence of bladder outlet obstruction in men with urinary symptoms

To determine whether prostate specific antigen (PSA) level can usefully predict or exclude bladder outlet obstruction (BOO), in men with lower urinary tract symptoms (LUTS).

A cohort of men from 1996 to 1999 who had LUTS caused by BPH was evaluated by serum PSA and pressure-flow urodynamic studies, and a blinded comparison made. The settings were teaching hospitals in London, UK and L'Aquila, Italy. Men (302) were referred by primary-care practitioners with LUTS and a PSA of < 10 ng/mL. Regression analysis was used to predict the extent of BOO, and create likelihood ratios and predictive values for BOO according to the PSA value.

PSA was significantly associated with BOO (P < 0.001; r2 0.07), with significant likelihood ratios altering the probability of BOO. If the PSA was > 4 ng/mL, mild or definite BOO was likely (89%), whereas if the PSA was <2 ng/mL, there was about a one-third chance each of no, mild and definite BOO.

High PSA levels in patients with LUTS are significantly associated with BOO; low PSA levels mean that definite BOO is unlikely.