Use of a urine enzyme immunoassay as a diagnostic tool for Chlamydia trachomatis urethritis in men

We collected first-voided urine specimens from 659 males attending a sexually transmitted disease clinic and performed both enzyme immunoassay (EIA) for detection of chlamydial antigen and leukocyte esterase testing on these urine samples. The overall prevalence of chlamydial urethritis in the study population as determined by culture of urethral swabs was 11%. However, 46% of all men in the study had no symptoms of urethritis. Compared with urethral cultures for chlamydiae, the urine EIA had a sensitivity of 42% and a specificity of 99%. The sensitivity of the EIA strongly correlated with the amount of antigen present in culture as assessed by numbers of inclusion-forming units. The sensitivity of the leukocyte esterase test compared with that of chlamydia culture was 88%. We conclude that in this population of men, which included many patients without symptoms of urethritis, the urine EIA was a relatively insensitive means of screening for chlamydial infection.