Highlights • Ct values of E gene were significantly lower than RdRp gene target. • COVID-19 case definition not specific, other respiratory viruses in 42 % of samples. • AusDiagnostics assay sensitive but not specific for the detection of SARS-CoV-2. Introduction There is limited data on the analytical performance of commercial nucleic acid tests (NATs) for laboratory confirmation of COVID-19 infection. Methods Nasopharyngeal, combined nose and throat swabs, nasopharyngeal aspirates and sputum was collected from persons with suspected SARS-CoV-2 infection, serial dilutions of SARS-CoV-2 viral cultures and synthetic positive controls (gBlocks, Integrated DNA Technologies) were tested using i) AusDiagnostics assay (AusDiagnostics Pty Ltd); ii) in-house developed assays targeting the E and RdRp genes; iii) multiplex PCR assay targeting endemic respiratory viruses. Discrepant SARS-CoV-2 results were resolved by testing the N, ORF1b, ORF1ab and M genes. Results Of 52 clinical samples collected from 50 persons tested, respiratory viruses were detected in 22 samples (42 %), including SARS CoV-2 (n = 5), rhinovirus (n = 7), enterovirus (n = 5), influenza B (n = 4), hMPV (n = 5), influenza A (n = 2), PIV-2 (n = 1), RSV (n = 2), CoV-NL63 (n = 1) and CoV-229E (n = 1). SARS-CoV-2 was detected in four additional samples by the AusDiagnostics assay. Using the in-house assays as the “gold standard”, the sensitivity, specificity, positive and negative predictive values of the AusDiagnostics assay was 100 %, 92.16 %, 55.56 % and 100 % respectively. The Ct values of the real-time in-house-developed PCR assay targeting the E gene was significantly lower than the corresponding RdRp gene assay when applied to clinical samples, viral culture and positive controls (mean 21.75 vs 28.1, p = 0.0031). Conclusions The AusDiagnostics assay is not specific for the detection SARS-CoV-2. Any positive results should be confirmed using another NAT or sequencing. The case definition used to investigate persons with suspected COVID-19 infection is not specific.
【저자키워드】 COVID-19, SARS-CoV-2, NAT, 【초록키워드】 SARS CoV-2, SARS-COV-2 infection, Sequencing, Multiplex PCR, sputum, influenza A, respiratory viruses, clinical samples, sensitivity, specificity, Culture, COVID-19 infection, rhinovirus, RSV, nucleic acid test, swabs, RdRP, viral culture, influenza B, Endemic, RdRp gene, ORF1ab, Negative predictive value, nose and throat, nasopharyngeal aspirate, CoV-229E, COVID-19 case, E gene, positive result, PCR assay, ORF1b, positive control, positive, NATs, laboratory confirmation, CoV-NL63, significantly lower, Integrated DNA Technologies, AusDiagnostics, AusDiagnostics assay, SARS-CoV-2 viral, serial dilution, clinical sample, Result, tested, collected, respiratory virus, was collected, applied, resolved, other respiratory virus, gBlocks, M genes, 【제목키워드】 SARS-CoV-2 virus, AusDiagnostics,