[Chlamydia diagnosis in clinical practice. Chlamydia trachomatis EIA and direct immunofluorescence (MikroTak) in...

The correct obtaining of material is decisive for microbiological diagnosis. The new immunologic methods, enzyme immunoassay (Chlamydiazyme) and the direct immunofluorescence with monoclonal antibodies (MikroTrak) for the detection of Chlamydia trachomatis have several advantages over cell culture. In 457 tests of urethral smears from men with all 3 methods, sensitivity and specificity were compared with cell cultures as method of reference. Tests with Chlamydiazyme yielded a concordance of 87.1%, a sensitivity of 81.5% and an specificity of 87.8%. Tests with MikroTrak were almost identical with a concordance of 86.9%, a sensitivity of 81.3% and a specificity of 87.5%. With both methods, the positive predictive value with 43.8% and 43.3% respectively is low. Frequent positive results with the immunological methods, which could not be verified by cell cultures, must be interpreted as failure of the culture method under practice conditions. The correlation of results with the clinical course supports this assumption.