Value of a DNA probe assay (Gen-Probe) compared with that of culture for diagnosis of gonococcal infection

Abstract

The Gen-Probe PACE 2 system for Neisseria gonorrhoeae (GP), which uses a chemiluminescently labeled DNA probe, was compared with conventional culture as the method of reference. A total of 1,750 specimens were collected from 496 females and 623 males visiting the outpatient clinic of the Sexually Transmitted Diseases Department of the Westeinde Hospital, The Hague, The Netherlands, during the year 1991. The prevalences of gonorrhea culture-positive men and women were 14.9 and 7.7%, respectively. The overall positive rate was 8.7%. Sensitivity, specificity, and positive and negative predictive values of GP were 97.1, 99.1, 90.6, and 99.8%, respectively. A total of 12 of 13 patients with positive GP results and negative cultures may have had a gonococcal infection, a conclusion based on clinical symptoms, positive methylene blue smears, and high relative light unit ratios. The DNA probe test can be useful as a suitable screening and diagnostic test for gonorrheal infection in men and women. An advantage of using this DNA probe technique is that simultaneous testing for Chlamydia trachomatis of the same specimen is possible. We also examined whether (all) rRNA had disappeared after adequate treatment for gonococcal and/or chlamydial infection in 30 patients. None of those positive patients showed a positive result in the DNA probe assay after treatment.