Abstract
BackgroundThe global burden of sexually transmitted infections (STIs) is high and there have been reports of increasing chlamydial and gonorrheal infections. High-volume screening programs for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are an important component of STI control. This study evaluated the high-volume workflow and performance of the cobas® CT/NG assay for use on the automated Roche cobas® 6800 system, with the cobas p 480 instrument for pre-analytics, compared with the Aptima Combo 2 assay on the Hologic Panther system.MethodsHigh-volume workflow and performance were evaluated using paired female urine specimens. Workflow analysis (n = 376) included hands-on time (HoT), number of manual interventions, and time to first and last results. For performance assessment, paired results from the cobas CT/NG and Aptima Combo 2 assays, for both CT and NG, were compared and two-sided 95% confidence intervals calculated to provide estimates of positive percent agreement (PPA), negative percent agreement (NPA), and overall percent agreement (OPA) between the tests. McNemar’s test was used for significance testing.ResultsPre-analytical preparations and system start-up on the cobas 6800 system required 00:27:38 (hr:min:sec) HoT whilst the Panther system required 00:30:43. The cobas 6800 system required eight interactions and 00:43:59 HoT to process 376 samples. The Panther system required six interactions and 00:39:10 HoT. Time to first results was 02:53:00 on the cobas c6800 system for 96 samples and 03:28:29 on the Panther system for five samples. The cobas 6800 system delivered all 376 results 3 h faster than the Panther system (07:45:26 and 10:47:30, respectively). The performance correlation between both assays was high (PPA, NPA and OPA > 99% for both CT and NG). McNemar’s test revealed no statistically significant difference between the assays.ConclusionFor high-volume automated CT/NG testing, both the cobas 6800 system and Panther system provided accurate results. Although less manual intervention steps were needed for the Panther system, improved turnaround time was obtained with the cobas 6800 system with less risk for contamination. The additional testing capacity on the cobas 6800 system would allow a growing service to deliver more results in a single shift.
Highlights
The global burden of sexually transmitted infections (STIs) is high and there have been reports of increasing chlamydial and gonorrheal infections
Study aim and design The objectives of this study were to compare the cobas Chlamydia trachomatis (CT)/Neisseria gonorrhoeae (NG) assay on the cobas® 6800 system, with the Aptima Combo 2 assay on the Panther system, evaluating the high-throughput workflow and assay correlation in female urine specimens
50 were excluded from the method correlation analysis because of suspected contamination at the time enrolled specimens were aliquoted for the study
Summary
The global burden of sexually transmitted infections (STIs) is high and there have been reports of increasing chlamydial and gonorrheal infections. Data from the USA have identified year-over-year increases in chlamydial and gonorrheal infections [2] Factors contributing to this include: the targeted expansion of screening practices; wider acceptance of HIV pre-exposure prophylaxis (with the resultant increase in condomless sex); and social networks with increased connectivity and the potential for sexual partners [2,3,4]. In this challenging environment, high-volume screening programs for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) are an important component of STI control [2, 5,6,7,8]. The cobas® CT/NG and Aptima Combo 2 assays are commercially available nucleic acid amplification tests with utility across different specimen types, including female urine [9, 10]
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