Detection of Chlamydia trachomatis in the urine of young Norwegian males by enzyme immunoassay.

First-void urine samples from 392 Norwegian military conscripts were investigated for the presence of Chlamydia trachomatis by enzyme immunoassay (EIA) on day 1 and day 5 after collection. Positive samples were subsequently investigated by direct immunofluorescence (IF) microscopy for the presence of chlamydial elementary bodies (EBs) in the urine pellet, and urethral swab material taken from the EIA-positive individuals was cultured. 4.8% (19/392) of the urine samples were EIA-positive on day 1, and 5.4% (21/392) were positive on day 5, with a combined total of 6.6% (26/392). Twenty-four of the 26 urine samples were confirmed as positive on IF microscopy. Urethral swabs were taken from 21 EIA-positive individuals. Six of the swabs were positive on cell culture, whereas nine were positive on IF microscopy of swab material, suggesting that these techniques perform better in symptomatic cases than in male Chlamydia trachomatis carriers. In the urine samples a notable discrepancy in EIA results was seen when the same refrigerated samples were retested on day 5 compared to day 1. This discrepancy was probably due to storage-related factors.