Comparison of DNA probe (Gen-Probe) with culture for the detection of Neisseria gonorrhoeae in an urban STD programme

Abstract

Background and Objectives: The DNA probe assay is an alternative to culture for the detection of Neisseria gonorrhoeae which does not depend on the viability of the organism. There have been few published studies comparing the two methodologies. The majority of these studies have shown the probe assay to be comparable to culture. The goal of this study was to compare the performance of the DNA probe assay with culture in a high prevalence setting with nearly optimal culture transport conditions. Methods: Genital specimens for culture and for DNA probe assay were collected at the time of the routine visit for STD clinic patients. Results of the two methods were compared. Discrepant results were further analysed using the results of direct patient Gram stains. Results: Satisfactory matched specimens were available for 999 patients. The overall sensitivity and specificity of the DNA probe as compared with culture was 90 and 96%. Resolved values achieved by factoring in the results of direct patient Gram stains did not significantly improve the performance of the probe. Conclusion: Culture remains the test of choice for the detection of gonorrhoea in a high prevalence setting where culture transport conditions are adequate.