[Study on Chlamydia trachomatis antigen detection by an EIA kit using a monoclonal antibody--comparison with a...

We evaluated the clinical usefulness of a new EIA kit using a monoclonal antibody, IDEIA CHLAMYDIA (IDEIA, Novo Nordisk), for detection of C. trachomatis antigen from the genital tracts of male and female cases. The results were compared with those by Chlamydiazyme (Abbott). 1. C. trachomatis antigen detection by the IDEIA and Chlamydiazyme tests before treatment; IDEIA has a significantly higher detection rate (38.0%, 105/276) than Chlamydiazyme (29.8%, 80/276), for C. trachomatis antigen from urethral smears of 276 male patients with urethritis. In 646 female cases, including cervicitis and so on, IDEIA detected C. trachomatis antigen from cervical smears in 14.5% (94/648) of the total, while Chlamydiazyme did so in 11.9% (77/648). When considering the different results using IDEIA and Chlamydiazyme, approximately 20% of the IDEIA-positive cases were Chlamydiazyme-negative. However, when IDEIA was negative, less than 1% showed Chlamydia-positive. 2. C. trachomatis antigen detection during and after treatment; We studied the clinical courses of 14 male urethritis and 8 female cervicitis cases who had had positive results with both IDEIA and Chlamydiazyme before treatment. Two of the 14 urethritis cases showed positive results with IDEIA, but not with Chlamydiazyme after either 7 or 14 days treatment by an antimicrobial agent. These two also had symptoms indicating persistent urethritis. One of the 8 female cervicitis cases showed a positive result with IDEIA but not with Chlamydiazyme after 7 days treatment by an antimicrobial agent, and this case also had symptoms indicating persistent cervicitis. Thus, these clinical findings suggest that IDEIA can detect even a small quantity of antigen soon after treatment, but Chlamydiazyme can not. In conclusion, IDEIA has a higher sensitivity than Chlamydiazyme, in the detection of C. trachomatis antigen, suggesting that IDEIA is more useful.