Diagnosis of Neisseria gonorrhoeae and Chiamydia trachomatis infection using first-voided urine in men with urethritis

A study was designed to examine the feasibility of making the specific diagnoses of gonorrhoea and chlamydia infection from a single specimen of urine. Urine specimens and urethral swabs were collected from 212 male attenders at a genitourinary medicine clinic who had evidence of urethritis. Urethral swabs and urine sediments were cultured for Neisseria gonorrhoeae and urine sediments were also tested by Gonozyme and IDEIA enzyme immunoassays for N. gonorrhoeae and Chlamydia trachomatis antigens respectively Sixty-three urethral cultures were positive for N. gonorrhoeae and 83 tests were positive in the routine amplified immunoassay for chlamydia antigen. Nineteen patients had a dual infection of gonorrhoea and chlamydia. The incidence of chlamydia in non-gonococcal urethritis was 43%, this closely agreed with our previous studies. Urine deposit and urethral swab culture for N. gonorrhoeae gave a concordant negative result in 148 patients and urine culture detected 61 out of 63 patients found positive by urethral swab culture, a sensitivity of 96.8%. The immunoassay for gonococcal antigen in urine detected 60 out of 63 urethral culture positive patients. If two persistently equivocal results were taken as reactive then the sensitivity of the test was 98.4% with a specificity of 94%. Our results showed that both N. gonorrhoeae and C. trachomatis can be detected readily using appropriate enzyme immunoassays on a single urine sample from symptomatic males. This approach to sexually-transmitted disease (STD) screening may be applicable to mass populations.