SARS-CoV-2 detection using digital PCR for COVID-19 diagnosis, treatment monitoring and criteria for discharge

Renfei Lu; Jian Wang; Min Li; Yaqi Wang; Jia Dong; Weihua Cai

3.1. Comparison of the lower limit of detection between dPCR and the standard RT-PCR 131 L ower limit of detection (LLoD) of RT-PCR and dPCR was compared using serial dilution of clinical 132 specimen. The starting clinical specimen showed Ct value of 35 in RT-PCR. The specimen was diluted 133 using virus storage solution. Each dilution was 5 fold. A total of 7 dilutions (8 samples S1-S8 134 including the starting stock) were tested by both RT-PCR and dPCR assays. As shown in Figure 1 and 135 Table 2 RT-PCR failed to detect S3, while dPCR was able to detect S3 and S4. dPCR showed 136 negative results for S5 through S8. dPCR assay showed at least 10 times lower LLoD than RT-PCR 137 assay. However. LLoQ (lower limit of quantification) was estimated to be larger than the viral 138 concentration in S3. 139 All rights reserved. No reuse allowed without permission. author/funder, who has granted medRxiv a license to display the preprint in perpetuity.