Article Text


Bacterial STIs
P71 Validation of an in house nucleic acid amplification (NAATs) PCR test for Trichomonas vaginalis
  1. J Appiah1,
  2. P Saunders2,
  3. M Yapa3,
  4. C Y W Tong3,
  5. J White3,
  6. C Ison2,
  7. S Alexander2
  1. 1Sexually Transmitted Bacteria Reference Laboratory, Health Protection Agency, London, UK
  2. 2Health Protection Agency
  3. 3Guys and St. Thomas Hospital NHS Trust, London, UK


Background Trichomonas vaginalis, a flagellated protozoan, is transmitted through sexual contact that commonly manifests itself as symptomatic in more women than men. However, the true prevalence of infection and the proportion that is asymptomatic is not known because of the lack of good diagnostic tests. Microscopy is the most common method of detection used but this is known to have a low sensitivity. Other methods include culture, which is considered the gold standard, a point of care test and molecular methods, which have increased sensitivity but are more time consuming or expensive.

Aim To validate an in-house nucleic acid amplification test (NAAT) test for the detection of T vaginalis.

Method Two methods were established In-house. The first NAATs detected T vaginalis by amplification of a 92 bp segment of the T vaginalis-specific repeat DNA fragment and the second amplified a segment of the â-tubulin gene, and was used to confirm the positive results. A further control ran alongside the first NAATs to identify inhibition by targeting the ribonuclease P gene. Sensitivity was initially validated with a positive control T vaginalis strain S1 and then validated against anonimised clinical samples previously tested using the APTIMA T vaginalis (ATV) transcription mediated amplification (TMA) kit and an in-house real-time TV PCR (see abstract P71 table 1).

Abstract P71 Table 1

TV diagnosed according to test

Results A total of 96 samples were tested. 17 (17.9%) of the specimens tested resulted in positive T vaginalis NAATs using both T vaginalis real-time PCR and the TV confirmatory real-time PCR.

Conclusions These in house NAATs gave good concordance with the commercial assay. It would be useful to further compare detection between this and other methods including the culture and POCT in asymptomatic patients. The methods established could also be used in comparisons in clinical studies.

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