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

Our DIRECT-PCR assay has been demonstrated on a commercially available portable thermocycler that weighs less than 2 kg, potentially allowing PCR to be performed outside molecular biology laboratories, in mobile laboratories, and in low resource settings. There are many real-time fieldable thermocyclers available, that are smaller, portable and less costly than benchtop ones, and three of these we have evaluated perform similar to benchtop ones (data not shown). While the optical detection modules and their fluorescence sensitivity vary between designs, the overall sensitivity of our assay was similar in both types of thermocyclers tested (Table 1) . Thermocycling parameters could also be optimized for rapidity (Fig. 3) . As the need to transport samples to central laboratories could prolong the availability of test results to beyond 24 hours (16), use of portable thermocyclers, coupled with appropriate training and quality control procedures, could allow the use of RT-qPCR nearer to the patients and in primary healthcare settings. Such rapid point-of-care (POC) tests for use at community level were identified by a WHO expert group as a key research priority (30). As the need to transport samples to central laboratories could prolong the availability of test results to beyond 24 hours (16), use of portable thermocyclers, coupled with appropriate training and quality control procedures, could allow the use of RT-qPCR nearer . CC-BY-NC-ND 4.0 International license author/funder. It is made available under a The copyright holder for this preprint (which was not peer-reviewed) is the .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 to the patients and in primary healthcare settings (12).