Evaluation of a new chemiluminometric immunoassay, Magic Lite Chlamydia, for detecting Chlamydia trachomatis antigen from urogenital specimens.

The chemiluminometric sandwich immunoassay, Magic Lite Chlamydia by Ciba Corning (Medfield, MA), using one Chlamydia trachomatis-specific monoclonal antibody conjugated with acridinium ester and one polyclonal immobilized to magnetic particles, was compared to cell culture in 291 urogenital specimens from 92 men and 102 women tested both in the cervix and urethra. The proportion of patients with positive culture results ranged from 11.8% among the women to 15% among the men, using microculture plates and peroxidase-antiperoxidase staining procedure with genus-specific monoclonal antibody (Orthodiagnostics, Raritan, NJ). The chemiluminometric method for detecting Chlamydia trachomatis antigen showed an overall sensitivity of 72.4%, specificity of 97.7%, positive predictive value of 77.7%, and negative predictive value of 96.9%. A higher sensitivity of Magic Lite was found in clinical specimens yielding more than 10 inclusions by well in cell culture. The newly developed chemiluminometric test, easy to perform, had the same limits in terms of sensitivity and positive predictive value than the other widely-used existing tests for detecting Chlamydia trachomatis antigen from urogenital specimens.