Analytical Validation of a COVID-19 qRT-PCR Detection Assay Using a 384-well Format and Three Extraction Methods

Andrew C Nelson; Benjamin Auch; Matthew Schomaker; Daryl M Gohl; Patrick Grady; Darrell Johnson; Robyn Kincaid; Kylene E Karnuth; Jerry Daniel; Jessica K Fiege; Elizabeth J Fay; Tyler Bold; Ryan A Langlois; Kenneth B Beckman; Sophia Yohe

A synthetic SARS-CoV-2 Standard control (Exact Diagnostics; abbreviated EDx) at 200 cp/µL viral nucleic acid and 75 cp/µL human gDNA was diluted into EDx Negative control (human only) as indicated. The EDx controls are manufactured to require extraction procedures to serve as a synthetic spike-in source for validation of the entire assay procedure and are ddPCR quality controlled for copy number. Synthetic viral RNA sources were acquired from BEI (NR-52358) and ATCC (VR3276T); a genomic isolate of USA-WA1/2020 was acquired from BEI. Plasmid cDNA was acquired from IDT encoding relevant target sequences from SARS-CoV-2 (nCov2, 10006625) as well as SARS (10006624) and MERS (10006623) viruses (to serve as specificity controls) and human RPP30 (RP, 10006626) as a control. Non-identifiable, residual clinical biospecimens were provided by the Minnesota Department of Health (MDH) for use under Common Rule exemption.