Saliva as an Alternate Specimen Source for Detection of SARS-CoV-2 in Symptomatic Patients Using Cepheid Xpert Xpress SARS-CoV-2
Clare McCormick-Baw, Kristi Morgan, Donna Gaffney, Yareli Cazares, Karen Jaworski, Adrienne Byrd, Kyle Molberg, Dominick Cavuoti
Abstract
Among the many facets of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is the unprecedented pressure it has placed on different points of the supply chain for hospital systems worldwide, such as collection devices for the diagnosis of COVID-19. The emergency use authorization of most of the commonly used platforms for SARS-CoV-2 testing is approved for nasopharyngeal swab (NPS) specimens. However, with the increasing need for alternative sources due to the NPS shortage, our institution sought to validate saliva specimens for the diagnosis of COVID-19 using the Cepheid Xpert Xpress SARS-CoV-2 (Sunnyvale, CA) PCR test. The Xpert SARS-CoV-2 assay is a sample-to-answer real-time reverse transcriptase PCR (RT-PCR) test with a run time of approximately 30 to 51 minutes (1). There are two targets, E and N2; the detection of both targets or N2 alone is considered positive, and the detection of E alone is considered presumptive positive.