Blueprint for a Pop-up SARS-CoV-2 Testing Lab

Jennifer A. Doudna

For each sample, three SARS-CoV-2 genomic targets are assayed. To return a positive diagnosis, the EUA for Thermo Fisher's TaqPath COVID-19 Combo Kit dictates that two out of the three gene targets must return a positive RT-qPCR result. In our setup this translates to a detected Ct value of less than 37 (but greater than zero) for two out of the three genes. The successful amplification of SARS-CoV-2 genomic targets can result in reduced MS2 amplification efficiency. Because of competition for PCR master mix reagents, it is possible that a highly amplified SARS-CoV-2 sample will present a low or undetected MS2 control. Thus, our decision criteria allow for a negative MS2 internal control when two out of three SARS-CoV-2 genomic targets test positive. To be able to return a negative result, the MS2 internal control must be positive. Additional criteria are listed in Table 2. 16 . CC-BY-ND 4.0 International license It is made available under a author/funder, who has granted medRxiv a license to display the preprint in perpetuity.