COMPARISON OF URINE WITH URETHRAL SWABS FOR THE DETECTION OF CHLAMYDIA-TRACHOMATIS IN MEN ATTENDING AN STD CLINIC

Urethral swabs and first-catch urine specimens for the detection of Ch lamydia trachomatis were collected from 370 black men with urethritis who attended a sexually transmitted disease (STD) clinic in Pretoria. An enzyme immunoassay (EIA) for C. trachomatis was carried out on all urethral swabs and urine specimens. Chlamydial culture and a direct im munofluorescent antibody (DFA) test (Imagen, Dako, UK) were also carri ed out on urethral swabs; DFA was used for confirmation of urine EIA p ositives, Based on culture and/or DFA, C. trachomatis was detected in 96 (26%) urethral swab specimens. The sensitivity of urine EIA investi gation was 94% and the specificity 99%, compared with those of urethra l swab EIA which were 97% and 99% respectively, The positive and negat ive predictive values for urine were 96% and 98% compared with 96% and 99% respectively for urethral swabs, Urine examination was therefore sensitive and specific compared with urethral swab examination in thes e STD patients. In view of this, the advantage of urine as an alternat ive to urethral swabs for C. trachomatis detection is that sampling is non-invasive and non-traumatic.