Counting leukocytes in expressed prostatic secretions from patients with chronic prostatitis/chronic pelvic pain syndrome

Abstract

Objectives: The evaluation of WBCs in EPS is recommended for classifying patients with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) but no agreement has been reached on the optimal method. We sought to determine the relationship between the expressed prostatic secretions (EPS) leukocyte (WBC) count per high-power field (evaluated by a more quantitative wet mount method and the traditional gram-stained smear method used in clinical microbiology laboratories) and the EPS WBC concentration to determine whether quantitative methods are necessary for accurate patient classification.

Methods: EPS collected from 94 patients with CP/CPPS were evaluated by gram-stained smear, a standardized wet mount, and a hemocytometer method.

Results: The gram-stained smear detected EPS WBCs in 21 (22%) of 94 subjects compared with 78 (83%) by the standardized wet mount and 57 (60%) by the hemocytometer method. The gram-stained EPS WBC count correlated poorly with the WBC concentration by hemocytometer (R(2) = 0.051, P = 0.03). Although the standardized EPS WBC count correlated better with the concentration by hemocytometer, the correlation coefficient remained low (R(2) = 0.244, P <0.0001).

Conclusions: The standardized wet mount proved superior to the gram-stained smear, but both methods lacked precision. Quantitative determination of the EPS WBC concentration by a counting chamber method proved to be the superior evaluation for research studies of CP/CPPS.