A comparison of urine sample to urethral swab for detection of Chlamydia trachomatis in asymptomatic young men using two enzyme immunoassays.

First catch early morning urine samples were compared to urethral swabs for detection of Chlamydia trachomatis in 405 male military conscripts, using 2 enzyme immunoassays, Syva Microtrak EIA (SME) and ABBOTT Chlamydiazyme (AC). The prevalence rate of C. trachomatis was 7.9% (95% confidence limits 5.5%-11.0%), and the asymptomatic carrier rate was 7.8% (95% confidence limits 5.2%-11.2%). Only 5 of 32 conscripts with positive test results for C. trachomatis complained of urethritis symptoms, and of 13 conscripts with symptoms, only 5 had positive test results for C. trachomatis. The sensitivity of SME in detecting C. trachomatis was 82.1% for both urine samples and urethral swabs. Assayed with AC, the sensitivity was 62.1% for urine samples and 41.4% for urethral swabs (P greater than 0.05). With urine as specimen type, the sensitivity of SME was 82.8% and the sensitivity of AC was 62.1% (P greater than 0.05). With urethral swab as specimen type, the sensitivity of SME was 92.3% and the sensitivity of AC was 46.1% (P less than 0.01). In all assays, the specificity was at least 98.0%. First catch early morning urine seems to be a valid specimen type for the detection of C. trachomatis in young men in comparison to ordinary urethral swab specimens. It is a noninvasive method and suitable for screening of asymptomatic young men.