Establishment and evaluation of fluorescent RT-RAA assay for SARS-CoV-2 sgRNAs detection

ABSTRACT

Objective To establish a reverse-transcription recombinase-aided amplification assay（RT-RAA） to rapidly detect SARS-CoV-2 sub-genomic RNAs（sgRNAs）. Methods The primers and probe for isothermal nucleic acid amplification were designed based on the 5′-leader and 7a and N gene sequence of SARS-CoV-2, and the sgRNAs of SARS-COV-2 were rapidly detected within 30 min at 39 ℃.The sensitivity, specificity and consistency of the assay were evaluated. Results The detection limit of the method was 20 copies/μl and there were no cross-reactions with other respiratory pathogens, showing decent sensitivity and specificity.The results of the assay were concordant with that of real-time PCR, indicating a better consistency of two methods（κ=0.762,P<0.001）. Conclusions The fluorescence RT-RAA assay established in the study can be used for the rapid detection of SARS-CoV-2 sgRNAs, which is of great significance for the rapid diagnosis of COVID 19.