P75 Comparison of Transcription-Mediated Amplification (TMA) and Polymerase Chain Reaction (PCR) Methods for Detection of Trichomonas Vaginalis From SUN Study Patients

Tuesday, March 9, 2010
Pre-Function Lobby & Grand Ballroom D2/E (M4) (Omni Hotel)
Kimberle C. Chapin, MD1, Sarah B. Andrea, BS1 and Milu M. Kojic, MD2, 1Department of Pathology, Rhode Island Hospital, Providence, RI, 2Immunology, The Miriam Hospital, Providence, RI

Background: Trichomonas vaginalis (TV) is the most common parasitic STI and associated with urogenital complications. While NAAT has shown superior sensitivity compared to wet mount and culture, limited comparison of different NAATs exists.

Objectives: To evaluate the sensitivity and specificity of PCR and TMA for TV detection in a population of patients enrolled in a long-term continuity of care study to understand the natural history of HIV/AIDS in the HAART era (SUN).

Methods: Urine and genital samples were collected during quarterly routine clinical evaluations. Genital swab specimens were analyzed by PCR utilizing a laboratory-developed assay targeting a repeated sequence of the TV genome and urines collected at the same visit, by an analyte-specific reagent (ASR) TMA test (Gen-Probe, Inc). All positives by TMA were subsequently analyzed with a research use only (RUO) TMA alternate probe set. Infection status was defined as 2 positives by 2 different NAATs. In addition, 266 negative specimens were analyzed using the RUO TMA-TV probe to determine TMA specificity.

Results: 946 urine and corresponding genital specimens collected from November 2004 to May 2008 were included. Negative and positive agreement by both NAATs was seen with 922(97.5%) and 20(2.1%) specimens, respectively. 4(0.4%) specimens were negative by PCR but positive by both sets of TMA probes. Sensitivity and specificity were 100% and 100% for TMA and 85.7% and 100% for PCR, respectively. TMA RUO probe testing with negative specimens yielded additional positives for an overall specificity of 98.5%.

Conclusions: Both NAAT methods were more sensitive than that reported in the literature for wet mount and culture. TMA identified 16.7% positives not detected by PCR. Urine was an adequate specimen for testing.

Implications for Programs, Policy, and/or Research: Ease of collection and increased sensitivity of detection of TV by TMA urine will allow identification of TV in at risk populations for STIs.

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