Detection of Chlamydia trachomatis in men. Sensitive tests for sensitive urethras.

The value of examining the centrifuged deposit from a first pass urine sample by an amplified enzyme-linked immunosorbent assay (ELISA) to detect Chlamydia trachomatis was assessed. The results were compared with those obtained by examining a urethral smear with a direct fluorescent antibody (DFA) test (MicroTrak; Syva, Palo Alto, CA). When the first pass urine sample yielded positive results for the IDEIA, but results of the DFA test of the corresponding urethral sample were negative, the remaining centrifuged deposit from the urine sample was examined by the DFA test. If results of this DFA test were positive, the IDEIA result was regarded as a true positive. Paired samples were collected by nursing staff from 190 men attending a clinic for sexually transmitted diseases (STDs). The quality of sampling thus reflected routine practice. The sensitivity of the IDEIA using first pass urine samples was 90% (37/41), and the sensitivity of the DFA test of urethral samples was 83% (34/41). The adoption of testing of first pass urine samples for the detection of C. trachomatis in STD clinics will not lead to a decrease in sensitivity for detecting C. trachomatis and will be more acceptable to patients than urethral swabbing.