Direct Detection of SARS-CoV-2 Using Reverse Transcription Loop-Mediated Isothermal Amplification (RT-LAMP) Without RNA Purification

Coronavirus disease 2019 (COVID-19) is an acute respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) which has spread globally. Shortage of nucleic acid extraction kits may delay the speed of diagnosis. In order to address this need, we propose a simple method for direct RNA extraction from nasopharyngeal swab samples without RNA purification. Here, we describe a reverse transcription loop-mediated isothermal amplification technique with 95.4% sensitivity (95% CI: 84.2-99.4%) and 100% specificity (95% CI: 78-100%). Combined with a simple RNA extraction step, this optimized RT-LAMP method is able to amplify SARS-CoV-2 directly from clinical nasopharyngeal swab samples in viral transport media in 50 minutes. This method provides an opportunity to facilitate SARS-CoV-2 detection especially in resource limited settings where nucleic acid extraction kits are few. Funding: This study was supported by Prototype Research Grant Scheme (PRGS), PR001-2020B (PRGS/2/2020/SKK09/UM/02/1) from the Ministry of Education, Malaysia. Declaration of Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this manuscript. Ethics Approval Statement: Ethical approvals for this study was obtained from UMMC 85 Medical Ethics Committee (202041-8418) and Medical Research Ethics Committee 86 (MREC) Ministry of Health Malaysia (NMRR-20-2344-56994).