Evaluation of an enzyme immunoassay (Chlamydiazyme) with confirmatory test for the detection of chlamydial antigen in urine from men.

First catch urine specimens from 312 male patients were examined for the presence of chlamydial antigen by an enzyme immunoassay (Chlamydiazyme). Positive results were repeated and confirmed using a blocking assay. In addition, urethral swabs were examined by cell culture for Chlamydia trachomatis. Discrepant results were further analysed by direct immunofluorescence (IF) of the spun urine deposit. Paired specimens were positive from 26 subjects, and negative from 276 subjects. Eight paired specimens were urethral culture positive, and urine EIA negative. Two specimens, urine EIA positive but urethral culture negative, were positive on direct IF. The sensitivity, specificity, predictive value of a positive result, and predictive value of a negative result for urine EIA against cell culture and/or direct IF were 77.8%, 100%, 100% and 97.2% respectively.