An assessment of real-time RT-PCR kits for SARS-CoV-2 detection

The COVID-19 outbreak caused by SARS-CoV-2 in Wuhan (China) in December 2019 is currently spreading rapidly and globally. We recently reported a laboratory diagnostic protocol for SARS-CoV-2 based on real-time RT-PCR assays using two primer sets, N and N2. On 30–31 January 2020, the protocol and reagents for these assays were distributed to local public health institutes and quarantine depots in Japan, and nationwide, SARS-CoV-2 diagnostic testing was started. For further validation, the assays were compared with the commercially available kits using SARS CoV-2 viral RNA and the clinical specimens obtained from COVID19-suspected individuals. The LightMix Modular SARS and Wuhan CoV E-gene (LN S&W-E) assay was highly sensitive for SARS-CoV-2, as was the N2 set, and both assays had perfectly consistent results with the clinical specimens. While the LM S&W-E set targets the highly conserved region of the E gene in SARS-CoV and SARS-CoV-2, the N2 set was designed to target the unique region in the SARS-CoV-2 N gene. Thus, the N2 set has high specificity and sensitivity for SARS-CoV-2 detection. These indicate that the protocol using the N and N2 sets is comparable to commercially available kits and is reliable for the laboratory diagnosis of COVID-19.