Enzyme immunoassay and enzyme-linked fluoroimmunoassay for detection of Chlamydia trachomatis antigen

An enzyme immunoassay (EIA) and an enzyme-linked fluoroimmunoassay (ELFIA) utilizing monoclonal antibody to major outer membrane protein of Chlamydia trachomatis L2 were developed for rapid detection of chlamydial antigen in clinical samples. The EIA and ELFIA could detect levels of purified chlamydial outer membrane protein as low as 1.0 and 0.2 ng/ml respectively. However, when EIA and ELFIA were compared to chlamydial isolation using 160 patient samples, the sensitivity rate was 68% and 85% respectively. The sensitivity of the antigen detection method might be increased by simply using less diluted samples than in the present study. Chlamydial antigen was also demonstrated by EIA and ELFIA in 15% and 23% of culture-negative samples. The reason for these false-positive findings remains undetermined.