Clinical Evaluation of the GeneXpert®Xpert®Xpress SARS-CoV-2/Flu/RSVPLUSCombination Test

Abstract

AbstractThe GeneXpert®Xpert®Xpress SARS-CoV-2/Flu/RSVPLUScombination test (PLUSAssay) received Health Canada approval in January 2022. ThePLUSAssay is similar to the SARS-CoV-2/Flu/RSV combination test, with modifications to improve assay robustness against circulating and emerging variants. The performance characteristics of thePLUSAssay were assessed at the Lakeridge Health Oshawa Hospital Centre and the National Microbiology Laboratory of Canada. ThePLUSAssay was directly compared to the SARS-CoV-2/Flu/RSV combination test using SARS-CoV-2 culture from five variants and remnant clinical specimens collected across the COVID-19 pandemic. This included 50 clinical specimens negative for all pathogens, 110 clinical specimens positive for SARS-CoV-2, Influenza A, Influenza B, RSVA, and/or RSVB and an additional 11 mixed samples to screen for target interactions. ThePLUSAssay showed a high percent agreement with the widely used SARS-CoV-2/Flu/RSV combination test. Based on these findings, thePLUSAssay and the Xpert SARS-CoV-2/Flu/RSV combination test results are largely consistent with no observed difference in sensitivity, specificity, or time to result when challenged with various SARS-CoV-2 variants. The reported Ct values provided by the newPLUSAssay was also unchanged, with the exception of a possible 1-2 decrease reported Ct for RSVA across a limited sample size.