Background To assess the performance characteristics of the Abbott m2000 (m2000), BD ProbeTec CT/GC Qx Amplified DNA Assay (Viper Qx), and COBAS 4800 (c4800) using oropharyngeal swabs (OP). This study may lead to additional diagnostic testing options for the identification of CT and GC using OP.
Methods De-identified, residual OP from a sequential convenience sample of patients attending an STD clinic for routine diagnostic testing was used for this comparison. Samples were collected using a BD culturette swab, and eluted into M4-equivalent culture medium (CTM) in the laboratory. Two-hundred ul of residual sample was added into each manufacturer’s collection device, which was subsequently tested on the Viper Qx, m2000, and c4800 systems per the package insert. A patient was considered infected if 2 of the 3 amplified test results were positive (PIS). The distribution of results across all three systems was assessed by Cochran’s Q test and between systems by McNemar’s chi-square. Agreement between each system and the PIS was assessed using Kappa statistics.
Results Two hundred and twenty one residual specimens were available for Viper Qx and m2000 testing; 216 for c4800. There was no statistical difference in performance between the three systems for GC (p = 0.174). For CT, there was a difference observed for both sensitivity and specificity when comparing all three systems (p = 0.018). However, there were no statistical differences in the distribution of results between systems in pair-wise comparison (all p > 0.125). Agreement was excellent for both CT and GC with κ-scores > 0.85 for CT and ≥ 0.95 for GC.
Conclusions There was no statistical difference in performance between the three systems for the detection of CT or GC using OP. All systems had very good agreement with the PIS, are user friendly, and will provide additional testing options for OP.
- Chlamydia trachomatis
- Neisseria gonorrhoeae
- oropharyngeal specimens