Pathfinder direct fluorescent antigen test for diagnosing maternal chlamydial infections. An evaluation

Chlamydia trachomatis is a frequent cause of genital infections in young women. Chlamydial infections may adversely affect perinatal outcome. We compared the Pathfinder direct fluorescent antigen (DFA) test for chlamydial infections to tissue culture isolation in an obstetric population. Among 984 samples, 152 (15.4%) were inadequate for evaluation using the Pathfinder DFA test. Among 783 evaluable specimen pairs, the sensitivity, specificity, and positive and negative predictive values of the Pathfinder, as compared to tissue culture isolation, were 25%, 97.5%, 32.1% and 96.4%, respectively. On the basis of that experience, we do not recommend the Pathfinder DFA test as a clinical screening device for detecting chlamydial infections complicating pregnancy.