Validation of the analytical performance of nine commercial RT-qPCR kits for SARS-CoV-2 detection using certified reference material

The ongoing coronavirus disease 2019 (COVID-19) pandemic has become a public health emergency. Although many reverse-transcription PCR (RT-PCR) assays have been developed, their performance, especially sensitivity assessment, has been insufficiently tested. In this study, a preliminary comparison of the analytical sensitivity of nine RT-qPCR kits from different manufacturers was first conducted using a certified reference material derived from the genomic RNA of SARS-CoV-2 as the template. Subsequently, three of the nine kits, comprising two highly sensitive kits (DAAN, Huirui) and one less sensitive kit (Geneodx), were selected for further sensitivity and specificity validation. The results revealed variations in the performance between kits of the two groups. For the two highly sensitive kits, the limits of detection at 95 % probability (LOD95%) were 5.6 copies of the N gene and 3.5 copies of the ORF 1ab per reaction (DAAN), and 6.4 (N) and 4.6 (ORF 1ab) copies per reaction (Huirui). These LOD95% values were approximately 3 to 4-fold better than those of the Geneodx Kit. However, none of these three Kits showed cross-reactivity against 6 other types of human coronaviruses or respiratory viruses. Because most of these commercial kits are approved as in vitro diagnostics (testing specimens without direct human contact), it would be beneficial for their manufacturers to improve the diagnostic capability of these kits and thus reduce the clinical risks associated with false-negative results.