Rapid direct nucleic acid amplification test without RNA extraction for SARS-CoV-2 using a portable PCR thermocycler

Soon Keong Wee; Suppiah Paramalingam Sivalingam; Eric Peng Huat Yap

Nasopharyngeal swabs and sputum have been suggested to be effective clinical samples for diagnosis (27, 28) , and we have assessed direct PCR using these matrices. It should be feasible to extend this to other common samples used for Covid- The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.04.17.042366 doi: bioRxiv preprint 19 testing, such as swabs of the throat and endotracheal tubes, and bronchoalveolar lavage fluid. While we have focused our DIRECT-PCR protocols on commonly used primer-probe sets developed by the China CDC and US CDC that target the SARS-CoV-2 N gene as well as ORF1ab gene and the internet control RP (data not shown), we expect direct PCR to be similarly useful for other viral primer targets and PCR amplicons developed for Covid-19 (8, 9) , as well as for multiplexed amplification of several targets in the same tube. Nevertheless, there may be other inhibitors of PCR that were not present in our samples that we tested, and clinical validation with a larger series is needed to exclude this possibility.