Rapid diagnosis of chlamydial infections with the MicroTrak direct test

A direct test on clinical specimens, using fluorescein-labeled monoclonal antibodies, for Chlamydia trachomatis (MicroTrak [Syva Co.]) was evaluated for the rapid diagnosis of chlamydial infections. Asymptomatic females attending pregnancy or planned parenthood clinics were tested by the direct test and by a cell culture method. Of 401 paired, endocervical specimens, 398 (99.3%) gave identical direct and culture results. The overall sensitivity of the direct test was 96.3% (26 of 27), and the specificity was 99.5% (372 of 374) as compared with that of culture. More than four-fifths of the direct smears were read within ca. 2 min. In this study population, the performance of the direct specimen test was comparable to that of cell culture methods. Rapid turnaround time and elimination of the need for cell culture make the direct test a practical method for the specific diagnosis of chlamydial infections.