Introduction Urine is the specimen of choice for CT and NG molecular testing from males and many of the next generation testing platforms are not FDA approved for use with urethral swabs. Urethral swabs remain valuable in research settings that may require that the specimen is collected in a manner preserving organism viability. The goal of this study was to assess the Abbott m2000 Realtime (m2000), and Roche COBAS 4800 (c4800) systems for the identification of CT and NG in urethral swabs collected in chlamydia transport medium (CTM).
Methods Archived male urethral swabs collected in CTM from STD clinic attendees were tested. These specimens were originally tested for CT and NG on a platform FDA-approved for urethral swabs collected in CTM (Roche COBAS Amplicor, (cAMP)).Two-hundred µl of CTM was added into each manufacturer’s collection device. This was subsequently tested on the m2000 and c4800 systems according to the manufacturer’s instructions. CT and NG results obtained from each platform were compared to the original cAMP results to determine sensitivity and specificity. Agreement between platforms was measured by calculating the kappa coefficient.
Results One hundred urethral swab specimens were available for testing (28 CT and 25 NG positives). When compared to results obtained with the cAMP, the sensitivity and specificity of the m2000 for the detection of CT was 100% and 98.6%, respectively; the sensitivity and specificity on the c4800 was 96.4% and 98.6%. For NG, the sensitivity and specificity of the m2000 assay was 100% and 98.7%; the c4800 assay was 100% sensitive and specific. Agreement was excellent for both platforms when compared to cAMP with kappa scores of >0.95 for CT and >0.97 for NG.
Conclusion The m2000 and c4800 platforms have similar performance characteristics to cAMP for the detection of CT and NG using urethral swabs in CTM. This study will provide investigators with additional options when designing protocols that require the preservation and ability to recover viable organisms from men.