THE TAMPON TEST FOR TRICHOMONIASIS - A COMPARISON BETWEEN CONVENTIONAL METHODS AND A POLYMERASE-CHAIN-REACTION FOR TRICHOMONAS-VAGINALIS INWOMEN

Objectives: Trichomonas vaginalis is the most common STD worldwide and the infection has been linked with an increased risk of HN transmissi on. We present a detailed comparison between conventional collection a nd testing methods and the polymerase chain reaction (PCR) tampon test for T vaginalis. Methods: Women were tested for the presence of T vag inalis by PCR analysis of a tampon specimen and by conventional method s which included one or more of the following: culture and microscopy from a high vaginal swab (HVS) or endocervical swab (ECS), and microsc opy of a Papanicolaou (Pap) smear. Results: T vaginalis was detected i n 51/590 (8.6%) conventional tests and 93/590 (15.8%) tampon specimens . Retesting of all tampon PCR positive specimens confirmed 89/93 (95.7 %) tests. Using the tampon PCR as the reference, the sensitivities of the different conventional sampling and testing methods for the detect ion of T vaginalis were 8.3% (5/60) for ECS microscopy or culture, 31% (13/42) for HVS microscopy or culture, 52.8% (19/36) for HVS directly inoculated into Trichomonas medium and 59.4% (38/64) for Pap smear. C onclusions: No conventional test in the remote setting has comparable sensitivity to PCR. The Pap smear is the next most sensitive, but requ ires a speculum examination. The use of PCR will allow inclusion of T vaginalis into STD screening programmes in both developed (lower preva lence) and developing (higher prevalence) countries.