Comparison of latex agglutination, wet preparation, and culture for the detection of Trichomonas vaginalis

Abstract

Objectives: To compare the performance of three diagnostic methods for Trichomonas vaginalis infection-latex agglutination, saline wet mount, and culture. Methods: Vaginal swabs from 3807 women attending antenatal clinics were tested for the presence of T vaginalis by latex agglutination. All positives and the following two negatives were tested by wet preparation and culture. Results: The prevalence of infection by latex agglutination was 5.4%. Using an expanded gold standard based on the wet mount and culture results, the sensitivity of the latex agglutination test was 98.8% (95% CI 95.9 to 99.9) and specificity was 92.1 (89.2 to 94.5). The kappa index for test agreement was 0.93 for latex and culture and 0.88 for latex and wet preparation. Conclusion:The latex agglutination test is a highly sensitive test for detecting T vaginalis infection. It is a simple rapid test and has the potential for use in screening and diagnostic settings. The highest prevalence of infection has been reported from resource constrained countries 2-4 and in disadvantaged populations in developed countries.5 Infection with T vaginalis may facilitate the transmission of HIV 6 7 and is associated with adverse pregnancy and perinatal outcomes.5 Thus, the control of T vaginalis infection is important in reproductive health settings and also in the control of HIV/AIDS. Diagnosis of T vaginalis infection in most parts of the world is carried out by the saline wet preparation (''wet prep'') method, a technique which has not changed since it was first reported by Donné in 1836.8 However, this technique has a low sensitivity of 30-80% [9][10][11] and requires trained and experienced microscopists. The gold standard in T vaginalis diagnosis-culture-has a higher sensitivity of 71-100%, 12 but requires an incubator with a constant electricity supply and relatively expensive culture media, in addition to an experienced microscopist. Further, it can take up to 7 days for results to be obtained, and currently is outside the reach of many health settings. In recent times, the sensitivity of T vaginalis diagnosis has been much improved by the use of nucleic acid amplification technology.13 14 Non-invasive diagnostic material (self obtained swabs, tampons, and urine) 15 16 appealing to patients, have also been used. Polymerase chain reaction (PCR) currently, however, is also outside the reach of many diagnostic centres in resource poor settings.A less technologically demanding technique with good test performance characteristics is needed, especially in resource poor countries. We compared a latex agglutination test with culture and Donné's wet prep technique for the diagnosis of T vaginalis infection. PATIENTS AND METHODSA total of 3807 consecutive women attending antenatal clinics in Kumasi, Ghana, were screened for vaginal infections between September 2002 and May 2003. Following informed consent, self administered vaginal swabs were screened for T vaginalis infection using the Kalon TV latex agglutination test (Kalon Biological, Surrey, UK...

Global epidemiology and control of Trichomonas vaginalis

“…In resource-limited settings antenatal or family-planning attendees are therefore often used as an indicator of the prevalence in the general population. Reported prevalence in these groups varies from 3.2 to 52%, similar to the prevalence reported in the general population above [42][43][44][45][46]57,58]. Antenatal studies from the USA also report high prevalence (7.6-12.6%), but this is likely to reflect high-risk groups in the general population [6,9].…”

Trichomoniasis and bacterial vaginosis in pregnancy: inadequately managed with the syndromic approach

“…Contrary to many other RTIs, simple and cheap tests for TV and BV are available. TV can be identified immediately with a simple latex agglutination test 43 or by saline wet preparation. BV can be diagnosed on-site, with or without the aid of a microscope.…”

Diagnosis of Vaginal Discharge by Wet Mount Microscopy: A Simple and Underrated Method

“…55,56 Recently, several alternative diagnostic bedside tests have been developed with reported sensitivities of 95% to 98.8% and specificities between 92.1% and 99%. 57,58 Additionally, nucleic acid amplification tests have been reported to have a greater sensitivity ranging …”