Clinical evaluation of the GeneXpert® Xpert® Xpress SARS-CoV-2/Flu/RSV combination test

Grant Johnson; Arek Zubrzycki; Michele Henry; Charlene Ranadheera; Cindi Corbett; Adrienne F A Meyers; Paul A Sandstrom; Michael G Becker

doi:10.1016/j.jcvp.2021.100014

Clinical evaluation of the GeneXpert® Xpert® Xpress SARS-CoV-2/Flu/RSV combination test

J Clin Virol Plus. 2021 Jun;1(1):100014. doi: 10.1016/j.jcvp.2021.100014. Epub 2021 Apr 12.

Authors

Grant Johnson^{1

2}, Arek Zubrzycki¹, Michele Henry³, Charlene Ranadheera⁴, Cindi Corbett^{4

5}, Adrienne F A Meyers^{5

6}, Paul A Sandstrom^{5

6}, Michael G Becker⁶

Affiliations

¹ Laboratory Medicine and Infection Prevention and Control, Lakeridge Health, Oshawa, Ontario L1G 2B9, Canada.
² Ontario Tech University, Oshawa, Ontario L1G 0C5, Canada.
³ Ontario Health, Toronto, Ontario, Canada.
⁴ Bacterial Pathogens Division, National Microbiology Laboratory, Canadian Science Centre for Human and Animal Health, Public Health Agency of Canada, Winnipeg R3E 3R2, Canada.
⁵ Department of Medical Microbiology and Infectious Diseases, University of Manitoba, Winnipeg R3E 0W2, Canada.
⁶ National HIV and Retrovirology Laboratories, National Microbiology Laboratory, JC Wilt Infectious Diseases Research Centre, Public Health Agency of Canada, Winnipeg R3E 3L5, Canada.

Abstract

The Cepheid Xpert Xpress SARS-CoV-2/Flu/RSV combination test received emergency use authorization approval by the United States Food and Drug Administration in December 2020, and Health Canada approval in January 2021. The performance characteristics of the GeneXpert Xpert Xpress SARS-CoV-2/Flu/RSV combination test were assessed at Lakeridge Health Oshawa and the National Microbiology Laboratory of Canada. The combination test was compared to the Xpert SARS-CoV-2 and Xpert Flu/RSV assays, and the BioFire FilmArray Respiratory Panel 2.1 (RP2.1) test kit. Materials evaluated were serial dilutions of chemically-inactivated SARS-CoV-2 and remnant clinical specimens (nasal or nasopharyngeal swabs) collected from patients. The limit of detection (LOD) for the SARS-CoV-2 component of the Xpert SARS-CoV-2/Flu/RSV combination test was determined to be <100 viral copies/mL when using chemically-inactivated SARS-CoV-2. In total, 86 clinical positive and 51 clinical negative samples were used for this study, with mixtures of clinical positives being used to mimic coinfection and screen for competitive inhibition. The combination test showed a high percent agreement with the Xpert SARS-CoV-2 and Xpert Flu/RSV tests, as well as the BioFire FilmArray RP2.1. Based on the findings from this study and a growing body of research, the Xpert SARS-CoV-2/Flu/RSV combination test will serve as an effective replacement for the Xpert SARS-CoV-2 and Xpert Flu/RSV assays.