Potential for routine concurrent determination of chlamydia and cervical abnormalities by single fluid-based sampling

Area of Science:

• Gynecologic pathology
• Infectious disease diagnostics
• Molecular diagnostics

Background:

• The ThinPrep(R) Pap test uses PreservCyt(R) Solution for fluid-based sample collection.
• FDA approval exists for adjunctive human papillomavirus (HPV) testing from this solution.
• Evaluating chlamydia testing from residual material in this sample is a logical extension.

Purpose of the Study:

• To assess the feasibility of routine chlamydia testing using residual cervical cellular material collected for ThinPrep(R) Pap screening.
• To compare the performance of direct fluorescence assay (DFA) and amplified DNA probe methods for chlamydia detection in this sample type.

Main Methods:

• Cervical scrapings were collected for conventional Pap smears and residual material was suspended in PreservCyt(R) Solution.
• Chlamydia testing was performed on the residual material using ThinPrep(R) slide preparation for DFA and a 1 mL aliquot for amplified DNA probe testing.
• Results were compared against a reference standard using an independent endocervical swab tested by direct DNA probe.

Main Results:

• The slide-based DFA method showed 84% sensitivity and 100% specificity.
• The amplified DNA probe method demonstrated 95% sensitivity and 99% specificity after resolving discrepant results.
• Both methods proved effective for chlamydia detection in the fluid-based sample.

Conclusions:

• Routine chlamydia testing is feasible using the same fluid-based sample collected for primary Pap screening.
• Both DFA and amplified DNA probe techniques can accurately detect chlamydia from this single sample.
• This approach streamlines sample processing and potentially reduces costs for co-testing.