EFFECT OF TIME ELAPSED SINCE PREVIOUS VOIDING ON THE DETECTION OF CHLAMYDIA-TRACHOMATIS ANTIGENS IN URINE

To determine if the time elapsed since previous voiding affects the se nsitivity of an enzyme immunoassay (EIA) to detect Chlamydia trachomat is in urine, 882 women and 428 men were tested for chlamydial infectio n in urethral specimens by isolation in cell culture (women and men) a nd EIA with blocking confirmation (women only). Of the 36 women (4.1 % ) and 38 men (8.9 %) who were positive for Chlamydia trachomatis in th e urethra, 55.5 % (20/36) and 81.6 % (31/38) respectively were positiv e in the first void urine (FVU) sediment by confirmed EIA. In women th e sensitivity of the EIA performed on FVU was 67.8 % (19/28) if the ur ine had been in the bladder < 3 hours and decreased to 12.5 % (1/8) if longer times had elapsed (odds ratio 13.7; 95 % confidence interval 1 .4 to 700.0) with no obvious confounding. In men a weaker association was present (odds ratio 2.7; 95 % confidence interval 0.4 to 22.3). Th ese findings should enable investigators to optimize the analysis of u rine to diagnose chlamydial infections.