Evaluation of the modified Chlamydiazyme immunoassay for the detection of chlamydial antigen.

The modified Chlamydiazyme enzyme immunoassay (EIA) was compared with McCoy cell culture with 336 paired genital swabs collected from patients attending gynecology and urgent care clinics and transported to the regional laboratory for testing. Of the 299 female and 37 male genital specimens, 47 (15.7%) cervical and 14 (37.8%) urethral specimens were positive. All 60 specimens positive for Chlamydia trachomatis also were EIA reactive (sensitivity, 100%). The specificity was 91.3%, with 24 paired swab specimens positive by EIA only. A number of factors may have contributed some culture false negatives, as 91.7% of the EIA only positive patients were symptomatic. The reproducibility of the EIA method was evaluated with different washing technics. The Chlamydiazyme EIA was found to be a cost-effective, rapid, and sensitive test for detection of chlamydial antigen in genital specimens.