One-step RNA extraction for RT-qPCR detection of 2019-nCoV

Monica Sentmanat; Evguenia Kouranova; Xiaoxia Cui

To determine if NP and OP specimens remain stable in QE buffer until they can be transported from the site of collection to the lab, we stored the samples with positive plasmid DNA template control at 100 copies/ul at room temperature, 4°C, or -20°C for 24 hours. Samples were heat extracted after 24 hours and used for the RT-qPCR test with probe sets N1 and N2. The sample without positive control added was processed for extraction immediately after the collection. All positive control samples had a Ct value between 33-34 for N1 and N2 across conditions. The Ct values for reference RNaseP were within the range of 26-29 when the collection swab was present during heat extraction and a Ct range of 29-31 when the swab was not present. This is consistent with epithelial cells being caught in the polyester fibers during collection. The spiked plasmid DNA does not seem to be retained on the swab. The Ct values of samples stored at different temperatures are not significantly different from those samples processed without storage (Table 1) .