Evaluation of a rapid diagnostic test for vaginal infections

Purpose: The diagnosis of vaginal discharge (VD) is usually based on vaginal ph, microscopic examination, KOH amine odor test and culture techniques. The purpose of this study was to evaluate a rapid and technically simple test (Affirm VP (TM) III, ED) which uses synthetic oligonucleotide probes for the simultaneous detection of Gardnerella vaginalis, Candida sp. and Trichomonas vaginalis from a single vaginal swab and to compare it with standard microscopic examination and culture. Material and Methods: A total of 317 samples including 17 defined laboratory specimens and 300 vaginal smears from women with clinical symptoms were processed. The vaginal fluid was collected with a swab (Port-A-Cul-System, ED) and transported to the laboratory within 24 hours. All specimens were examined by wet-mount, gram-stain and conventional culture. The Affirm test was applied to the rest of the vaginal fluid. Results: All laboratory specimens were confirmed by the Affirm test and the standard methods. From the 300 patient samples 125 specimens showed a positive result. These isolates included 67 Candida sp., 68 Gardnerella vaginalis and 1 Trichomonas vaginalis. 175 specimens had no laboratory signs of abnormal VD. Physiologic flora was present in all specimens. Discrepancies between conventional methods and the hybridisation test were found in 3 cases: 2 fungal cultures with non-significant growth of Candida sp. (< 10000 cfu/ml) were Affirm and microscopy negative and 1 positive Affirm test was culture and microscopy negative. 12 women had mixed infections. All of them were confirmed by both systems. Conclusion: The Affirm VP (TM) III test compared well with the microscopic examination and culture of vaginal fluid in detecting clinically significant levels of Candida sp., and Gardnerella vaginalis from a single swab but is less time-consuming and labor-intensive.