EVALUATION OF AN IMMUNOCHROMATOGRAPHIC DIP STICK TEST FOR THE DIAGNOSIS OF VAGINAL TRICHOMONIASIS IN COMPARISON WITH WET MOUNT AND CULTURE
Amany A. Abd El-Aal11, Fawzia A. Habib2 and Lobna M. Saber3
1Department of Parasitology, Faculty of Medicine, Cairo University
2Department of Obstetric and Gynaecology, Faculty of Medicine, Taibah University, Saudi Arabia and
3Department of Biochemistry, Faculty of Medicine, Al-Azhar, University, Egypt
The purpose of this study was to evaluate the performance of XenoStrip test, a new diagnostic assay for vaginal trichomoniasis which is an immuno-chromatographic antigen detecting capillary flow (dipstick) assay that provides results within 10 minutes, utilizing immunoglobulin G1 monoclonal antibodies XDTv1 and XDTv2 to target intracellular and surface secretory proteins. The prospective, cross-sectional study enrolled women who presented with symptoms of vaginitis. High vaginal swab specimens were obtained and examined for T. vaginalis by wet mount, XenoStrip rapid testing and In-Pouch TV culture that was considered the gold standard diagnostic method in this study. The results of the XenoStrip test and wet mount microscopy were compared to In-Pouch TV system. The control group for the immunochromatographic test was obtained by collecting 20 specimens from randomly selected culture-negative women and 24 samples from patients with negative culture for trichomoniasis, but positive for other vaginal infections. Of 28 women with positive culture, only 18 were diagnosed by wet microscopy, thus the recorded sensitivity of wet mount was 64.3% (95% CI: 44.1-80.7%). The XenoStrip correctly identified 6 out of the remaining 10 cases that obtained positive culture results but were negative by wet mount test, therefore, the reported sensitivity of XenoStrip was 85.7% (95% CI: 66.4-95.3%). One false positive result was observed with the rapid test from the 20 culture-negative samples, thus recording specificity of 97.8% (95% CI: 86.8-100%). XenoStrip performed significantly better than wet mount (p < 0.05) and was able to detect T. vaginalis in samples that required 48 to 72 hours of incubation prior to becoming culture positive. The XenoStrip Rapid Test for Trichomonas is a simple, objective test that can be expected to improve the diagnosis of T. vaginalis, especially where microscopy and culture are unavailable.