Analytical Performance of the Transcription-Mediated Amplification (TMA) Trichomonas vaginalis Assay in Liquid-based Cytology Media

Background:
Trichomoniasis is a sexually transmitted infection caused by the protozoan Trichomonas vaginalis (TV). While often asymptomatic, TV infections can cause adverse health consequences, including pelvic inflammatory disease and increased risk of acquiring HIV. Each year, 5 to 7 million new TV infections occur in the United States. The ability to detect TV from Cytyc ThinPrep liquid-based cytology (LBC) media would allow for convenient detection and treatment of trichomoniasis in asymptomatic women undergoing routine pelvic cytology examination.

Objective:
To determine the analytical performance of a TMA-based TV assay in Cytyc ThinPrep LBC media.

Method:
The TMA-based TV assay uses TV-specific oligonucleotides added to APTIMA® General Purpose Reagents (GPRs) and follows the APTIMA assay format with a 400uL sample undergoing target capture followed by TMA and Hybridization Protection Assay (HPA) on the semi-automated DTS® System. Analytical sensitivity was tested in a 1:2.9 mixture of ThinPrep media and APTIMA Specimen Transport Medium (STM) spiked with TV to concentrations of 0.001 to 10 cell-equivalents per reaction. Cross reactivity with over 20 closely related microorganisms and common urogenital flora was also tested in ThinPrep media+STM mixture. Finally, stability of TV cells in ThinPrep media at 30°C and 4°C was studied.

Result:
The TMA-based TV assay showed 100% analytical sensitivity at 0.001 cell-equivalents per reaction and did not exhibit any cross reactivity with the microorganisms tested. TV cells were stable in ThinPrep media for 21 days at 30°C and 4°C.

Conclusion:
These data show that TV cells are stable and can be readily detected with high analytical sensitivity and specificity from Cytyc ThinPrep LBC media.

Implications:
This work provides the basis for a study of TMA-based TV assay performance in clinical samples collected in Cytyc ThinPrep media.