A molecular test based on RT-LAMP for rapid, sensitive and inexpensive colorimetric detection of SARS-CoV-2 in clinical samples

Abstract Until there is an effective implementation of COVID-19 vaccination program, a robust testing strategy, along with prevention measures, will continue to be the most viable way control disease spread. Such strategy should rely on disparate diagnostic tests prevent slowdown in due lack materials and reagents imposed by supply chain problems, which happened at beginning pandemic. In this study, we have established single-tube test based RT-LAMP that enables visual detection less than 100 viral genome copies SARS-CoV-2 within 30 min. We benchmarked assay against gold standard for diagnosis, RT-PCR, using 177 nasopharyngeal RNA samples. For loads above copies, had sensitivity 100% specificity 96.1%. Additionally, set up extraction-free capable detecting directly from saliva samples, albeit lower sensitivity. The was self-collected collection tube remained closed until inactivation, thereby ensuring protection personnel. As expected, extraction samples increased test. To costs associated extraction, performed step alternative protocol uses plasmid DNA columns. also produced enzymes needed in-house-made independent specific distribution channels. Finally, developed new colorimetric method allowed LAMP products visualization evident color shift, regardless reaction pH.