Timing of inoculation of the pouch makes no difference in increased detection of Trichomonas vaginalis by the InPouch TV method

Abstract

The InPouch TV is a method which combines a wet preparation and a culture method to detect Trichomonas vaginalis. The top portion of the InPouch TV essentially functions as a slide to be examined under the microscope. If the initial examination is negative, the specimen is pushed down into the bottom pouch, which serves as a broth for cultivation. The issue of timing has not been specifically addressed for optimal processing. To assess the effect of timing on the inoculation of the bottom pouch, we conducted a study designed to determine which procedure had better sensitivity, that of delaying inoculation of the bottom pouch until the initial examination on the top pouch is performed (method A) or that of immediately inoculating the bottom pouch (method B). In addition, we compared the sensitivity of the InPouch TV to that of the traditional wet mount. Fifty of 498 specimens were positive. Methods A and B had identical results: 31 specimens were initially positive regardless of transit time, and incubation yielded another 19 positives. The wet preparation detected 36 positive specimens. The sensitivities of the methods were 100% for the InPouch TV (including examination on receipt and after incubation) and 72% for the traditional wet mount. In conclusion, the InPouch TV method is more sensitive than the traditional method and no detectable differences were observed with timing of the inoculation of the top or bottom pouch.

FIG. 1.

Diagram of InPouch TV.