Use of a direct fluorescent antibody test for detecting Chlamydia trachomatis cervical infection in women seeking routine gynecologic care.

We determined the sensitivity, specificity, and predictive value of a direct fluorescence test for Chlamydia trachomatis infection compared with culture of the endocervix in women seeking routine gynecologic care. Of 527 patients seen in a hospital-based practice, 23 (4.4%) had a positive culture for C. trachomatis. The overall sensitivity of the direct test was 70%, and the specificity was 98%. When five or more endocervical cells were present on the direct test slide, the sensitivity increased to 92%, and the specificity decreased to 96% (P less than .05). When the presence of any columnar epithelial cells, five or more elementary bodies, or both was used as the criteria for accepting specimens, the sensitivity and specificity of the direct test were 80% and 96%, respectively. However, 44% of the specimens would be rejected if these criteria were used. The overall probability that an individual with a positive direct test would have a positive culture was 62%.