Culture-independent diagnosis of Chlamydia trachomatis using monoclonal antibodies

To simplify the diagnosis of chlamydial genital infection, we used a fluorescein-conjugated monoclonal antibody in immunofluorescence tests on smears prepared from urethral or cervical secretions obtained directly from patients. This direct test, requiring less than 30 minutes to perform, was based on the detection of extracellular chlamydial elementary bodies. A comparison of the direct test with cultures stained with iodine on specimens from 926 patients demonstrated a sensitivity of 93 per cent and a specificity of 96 per cent. The direct test provides a rapid, simple, and sensitive method for the diagnosis of chlamydial infection, which can be performed in laboratories that do not have tissue-culture capability.