Abstract

COSTAMAGNA, Sixto Raúl; DUPIN, Javier; VAYLET, Susana  and  PELLEGRINO, Patricia. Evaluation of metilene blue staining-fixing technique for diagnosis of Trichomonas vaginalis. Acta bioquím. clín. latinoam. [online]. 2004, vol.38, n.3, pp.307-309. ISSN 0325-2957.

Trichomonas vaginalis laboratory diagnosis is still the focus of attention of several research studies. Mendez et al have proposed a staining-fixing technique for the wet mount examination of this flagellate. The purpose of the present study is to examine the validity of such proposal against the conventional wet mount examination. For this purpose, a hundred vaginal secretions were analyzed. They were obtained from the vaginal cavity of female subjects to whom a microbiological examination had been requested. Samples were collected and processed following Méndez et al's technique. In parallel, and before an hour of obtention had elapsed, a conventional wet mount examination of the obtained material was carried out between the slide and cover glass and with no staining solution. The results obtained were analyzed with EpiDat Software from PAHO/WHO. The total of positive results in both tests was considered as reference test. The results derived from the present study with a 95% confidence level were, for conventional wet mount examination: Sensitivity 66.6%, Specificity 100%, Predictive Value of Positive Result (PVPR) 100%, Predictive Value of Negative Result (PVNR) 93.93% and Global Value of the Test 94.59% and ratio of verisimilitude negative 0.33. For the staining-fixing technique, Sensitivity, Specificity, PVPR, PVNR, Global Value of the Test were 100% and ratio of verisimilitude negative was 0.00. Based on its specificity, diagnostic sensitivity, PVPR, and PVNR, and in view of our results, it can be concluded that staining-fixing technique could be recommended either as a second test or instead of the conventional wet mount examination for the direct diagnosis of T. vaginalis in vaginal secretions.

Keywords : Trichomonas vaginalis; Trichomonosis; Parasite; Diagnosis.

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