Validation of the GeneXpert Xpress SARS-CoV-2 PCR assay using saliva as biological specimen

• Published in: The Brazilian journal of infectious diseases Vol. 25; no. 2; p. 101543
• Main Authors: Vaz, Sara Nunes, Santana, Daniele Souza de, Netto, Eduardo Martins, Wang, Wei-Kung, Brites, Carlos
• Format: Journal Article
• Language: English
• Published: Brazil Elsevier España, S.L.U 01.03.2021; Contexto; Elsevier; Brazilian Society of Infectious Diseases
• Subjects: Biochemical assays; Brief Communication; Clinical Laboratory Techniques; COVID-19; COVID-19 Testing; Diagnostics; GeneXpert; Humans; INFECTIOUS DISEASES; Methods; Molecular diagnostic techniques; Nasopharynx; Pandemics; Polymerase Chain Reaction; Saliva; Salivary diagnostics; SARS-CoV-2; Sensitivity and Specificity; Specimen Handling; Brazil; SARS-CoV-2; Diagnostics; Saliva; GeneXpert
• ISSN: 1413-8670; 1678-4391; 1678-4391
• DOI: 10.1016/j.bjid.2021.101543

In the pandemic, rapid and accurate detection of SARS-CoV-2 is crucial in controlling the outbreak. Recent studies have shown a high detection rate using saliva/oral fluids as specimens for laboratory detection of the virus. We intended to evaluate the test performance of the Xpert Xpress SARS-CoV-2 cartridge assay in comparison to a conventional qRT-PCR testing, using saliva as biological specimen. Forty saliva samples from symptomatic participants were collected. Conventional qRT-PCR was performed for amplification of E and RdRp genes and the Xpert Xpress SARS-CoV-2 assay amplified E and N2 genes. In the conventional assay, the median cycle threshold value of the E gene was 34.9, and of the RdRp gene was 38.3. In the Xpert Xpress assay, the median cycle threshold value of the E gene was 29.7, and of the N2 gene was 31.6. These results can allow a broaden use of molecular tests for management of COVID-19 pandemic, especially in resources-limited settings.