Comparison of three TaqMan real-time reverse transcription-PCR assays in detecting SARS-CoV-2

Quick and accurate detection of SARS-CoV-2 is critical for COVID-19 control. Dozens of real-time reverse transcription PCR (qRT-PCR) assays have been developed to meet the urgent need of COVID-19 control. However, methodological comparisons among the developed qRT-PCR assays are limited. In the present study, we evaluated the sensitivity, specificity, amplification efficiency, and linear detection ranges of three qRT-PCR assays, including the assays developed by our group (IPBCAMS), and the assays recommended by WHO and China CDC (CCDC). The three qRT-PCR assays exhibited similar sensitivities, with the limit of detection (LoD) at about 10 copies per reaction (except the ORF 1b gene assay in CCDC assays with a LoD at about 100 copies per reaction). No cross reaction with other respiratory viruses were observed in all of the three qRT-PCR assays. Wide linear detection ranges from 10⁶ to 10¹ copies per reaction and acceptable reproducibility were obtained. By using 25 clinical specimens, the N gene assay of IPBCAMS assays and CCDC assays performed better (with detection rates of 92 % and 100 %, respectively) than that of the WHO assays (with a detection rate of 60 %), and the ORF 1b gene assay in IPBCAMS assays performed better (with a detection rate of 64 %) than those of the WHO assays and the CCDC assays (with detection rates of 48 % and 20 %, respectively). In conclusion, the N gene assays of CCDC assays and IPBCAMS assays and the ORF 1b gene assay of IPBCAMS assays were recommended for qRT-PCR screening of SARS-CoV-2.