Abstract:
Wet mount microscopy is the most commonly used diagnostic method for
trichomoniasis in clinical diagnostic services all over the world including Sri Lanka due to its
availability, simplicity and is relatively inexpensive. However, Trichomonas culture and PCR
are the gold standard tests. Unfortunately, neither the culture nor PCR is available for the
diagnosis of trichomoniasis in Sri Lanka. Thus, it is important to validate the wet mount
microscopy as it is the only available diagnostic test and has not been validated to date in Sri
Lanka. The objective was to evaluate the validity and reliability of wet mount microscopy
against gold standard Trichomonas culture among clinic based population of reproductive
age group women in Western province, Sri Lanka. Women attending hospital and institutional
based clinics were enrolled. They were interviewed and high vaginal swabs were taken for
laboratory diagnosis by culture and wet mount microscopy. There were 601 participants in
the age group of 15-45 years. Wet mount microscopy showed 68% sensitivity, 100% specificity,
100% positive (PPV) and 98% negative predictive values (NPV) (P=0.001, kappa=0.803)
respectively against the gold standard culture. The area under the ROC curve was 0.840.
Sensitivity of wet mount microscopy is low. However it has high validity and reliability as a
specific diagnostic test for trichomoniasis. If it is to be used among women of reproductive
age group in Western province, Sri Lanka, a culture method could be adopted as a second test
to confirm the negative wet mount for symptomatic patients.
