Chlamydia trachomatis and Pap testing from a single, fluid-based sample - A Multicenter study

OBJECTIVE: To determine the potential for both Pay testing and the Chlamydi a direct fluorescence assay (DFA)from a single sample using the fluid-based ThinPrep(R) Pnp Test(TM) method (Cytyc Corporation, Boxborough, Massachuse tts). STUDY DESIGN: Conventional DFA was compared to ThinPrep(R) DFA in a direct- to-vial, double-blinded, multicenter protocol. Cervical scrapings were coll ected for the ThinPrep(R) Pap Test, and then a second swab was used to coll ect an endocervical sample for a conventional DFA test. The DFA slide prepa red from the ThinPrep(R) Test and the conventional DFA sample prepared from the endocervical swab were evaluated independently. Discrepant cases were adjudicated by testing residual specimens using a Chlamydia divert DNA meth od. RESULTS: Combining 636 adequate cases (94% of the total collected), 582 (91 .5%) were negative on both slides, 43 (6.8%) positive by kboth and 11 (1.7% ) discrepant. The prevalence of Chlamydia was 7.9% based on the conventiona l DFA method (range, 4.3-10.9%). McNemar's two-tailed test indicated the re sults not to be statistically different (P > .05). Adjudication favored Thi nPrep(R) 45% of the time and conventional 55%. Specimen adequacy favored Th inPrep with high statistical significance (McNemar's test, P > .01). CONCLUSION: A second slide prepared from the same vial of cells as that use d for the ThinPrep(R) Pap Test can be used for Chlamydia resting by DFA. Fl uid-based collection could allow multiple tests from a single sample.