LAUSR

The Cepheid(R) GeneXpert(R) Xpert(R) Xpress SARS-CoV-2/Flu/RSV PLUS combination test (PLUS Assay) received Health Canada approval in January 2022. The PLUS Assay is similar to the SARS-CoV-2/Flu/RSV combination test, with the exception of an additional SARS-CoV-2 target that was included to improve assay robustness against emerging variants. The performance characteristics of the SARS-CoV-2/Flu/RSV PLUS combination test were assessed at the Lakeridge Health Oshawa Hospital Centre and the National Microbiology Laboratory of Canada. The PLUS Assay was directly compared to the Xpert Xpress SARS-CoV-2/Flu/RSV combination test using SARS-CoV-2 culture from five variants and remnant clinical specimens collected across multiple waves of the COVID-19 pandemic. This included 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. Additionally, 50 samples negative for all pathogens were included in this comparison. The PLUS Assay showed a high percent agreement with the widely used SARS-CoV-2/Flu/RSV combination test. Based on the findings from this study, the PLUS Assay and the Xpert SARS-CoV-2/Flu/RSV combination test results are largely consistent as there was no observed difference in sensitivity, specificity, reported Ct value, or time to result when challenged with various SARS-CoV-2 variants.