Multicenter clinical evaluation of Revogene® Strep A molecular assay for detection of Streptococcus pyogenes from throat swab specimens

Group A Streptococcus (GAS) causes bacterial pharyngitis in both adults and children. Early and accurate diagnosis of GAS is important for appropriate antibiotic therapy to prevent GAS sequalae. The Revogene® Strep A molecular assay (Meridian Bioscience Canada Inc, Quebec City, QC) is an automated real time PCR assay for GAS detection from throat swab specimens within approximately 70 minutes. This multicenter prospective study evaluated the performance of Revogene Strep A molecular assay compared to that of bacterial culture. Dual throat swab specimens in either liquid Amies or Stuart medium were collected from eligible subjects (pediatric population and adults) enrolled across 7 sites (USA and Canada). Revogene Strep A and reference testing was performed within 7 days and 48 hours of sample collection respectively. Of the 604 evaluable specimens, GAS was detected in 154 (25.5%) samples by reference method and 175 (29%) samples by Revogene Strep A assay. Revogene Strep A assay sensitivity and specificity were reported to be 98.1% (95% confidence interval [lsqb]CI[rsqb], 94.4 - 99.3) and 94.7% (95% CI 92.2 - 96.4) respectively. The positive predictive value was 86.3% (95% CI 80.4 - 90.6), negative predictive value was 99.3% (95% CI 98.0 - 99.8) with 1.0% invalid rate. Discrepant analysis with alternative PCR/bidirectional sequencing was performed for 24 false positive (FP) and 3 false negative (FN) specimens. Concordant results were reported for 17 (FP only) of 27 discordant specimens. Revogene Strep A assay had high sensitivity and specificity for GAS detection and provides a faster alternative for GAS diagnosis.