Polymerase chain reaction versus conventional methods in the diagnosis of vaginal trichomoniasis

A total of 200 females of whom 120 had manifestations of vaginal trichomoniasis and 80 asymptomatic ones were studied. In 54/120 symptomatic female (45%) and in 28/80 asymptomatic ones (35%), T. vaginalis was diagnosed by wet mount of bedside vaginal swab samples. Of 120 samples from symptomatic females, T. vaginalis was detected in 93 (77.5%) when cultured onto InPouch & 95 (79.16%) in modified thioglycolate media. Culturing 80 samples of asymptomatic females showed T. vaginalis in 35 (43.75%) onto either media. T. vaginalis genomic DNAs was amplified by PCR from 130 (65%) by using TVA5-TVA6 primer pair in 95 (79.16%) samples of 120 symptomatic females, and in 35 (43.75%) samples of 80 asymptomatic ones. Difference between groups was statistically significant. The motile trichomonads was detected by wet mount in 82/130 positive cultures giving 63.07% sensitivity & 100% positive predictive value (PPV). Flagellates were not detected by wet mount in any negative culture, giving 100% specificity & 59.32% negative predictive value (NPV). The wet mount diagnostic accuracy (DA) was 76%, without false-positive, but false negative was 48/130 (36.93%). DNA was amplified from 129/130 positive culture by TVA5-TVA6 primer pair, giving 99.23% sensitivity. No amplification was detected from one positive culture. DNA was not amplified from 69/70 negative culture using TVA5-TVA6 primer pair, giving 98.57% specificity, 99.23% PPV, 98.57% NPV and 99% DA.