[Diagnosis of Chlamydia trachomatis--culture or enzyme immunoassay? Norwegian multicenter study]

Two EIA-tests (Chlamydiazyme, Abbott and Ideia, Celltech) were compared with culture for diagnosis of chlamydial infection in 1,185 patients from four different regions in Norway. The EIA-tests showed only minor differences in prevalences between the different regions (Chlamydiazyme: 4.1% to 5.4%; Ideia: 5.1% to 5.7%), but the agreement between the EIA-results was not satisfactory. 4.6 per cent of the specimens from Trondheim were culture-positive, but only 2.0% of the specimens from the other regions were culture-positive. Compared with the results from cultures from Trondheim (n = 349), the sensitivity, specificity, positive and negative predictive values for the EIA-tests were: Chlamydiazyme: 81.3%, 98.2%, 68.4% and 99.1% (81.3%, 96.4%, 52.0% and 99.1% without blocking test); Ideia: 93.8%, 98.5%, 75.0% and 99.7%. Culture should not be used as a routine method for detection of chlamydia in specimens sent by post without cooling.