Agile design and development of a high throughput cobas(R) SARS-CoV-2 RT-PCR diagnostic test

Manohar, C.; Sun, J.; Schlag, P.; Santini, C.; Fontecha, M.; Lotscher, P.; Bier, C.; Goepfert, K.; Duncan, D.; Spier, G.; Jarem, D.; Kosarikov, D.

Diagnostic testing is essential for management of the COVID-19 pandemic. An agile assay design methodology, optimized for the cobas(R) 6800/8800 system, was used to develop a dual-target, qualitative SARS-CoV-2 RT-PCR test using commercially available reagents and existing sample processing and thermocycling profiles. The limit of detection was 0.004 to 0.007 TCID50/mL for USA-WA1/2020. Assay sensitivity was confirmed for SARS-CoV-2 variants Alpha, Beta, Gamma, Delta and Kappa. The coefficients of variation of the cycle threshold number (Ct) were between 1.1 and 2.2%. There was no difference in Ct using nasopharyngeal compared to oropharyngeal swabs in universal transport medium (UTM). A small increase in Ct was observed with specimens collected in cobas(R) PCR medium compared to UTM. In silico analysis indicated that the dual-target test is capable of detecting all >1,800,000 SARS-CoV-2 sequences in the GISAID database. Our agile assay design approach facilitated rapid development and deployment of this SARS-CoV-2 RT-PCR test.