A Simple, Affordable, Rapid, Stabilized, Colorimetric, Versatile RT-LAMP Assay to Detect SARS-CoV-2

TLDR: In this paper, the reverse-transcription loop-mediated isothermal amplification (RT-LAMP) can be used as an alternative testing method for SARS-CoV-2 targeting both ORF1ab and N genes.

Abstract: The SARS-CoV-2 pandemic has forced all countries worldwide to rapidly develop and implement widespread testing to control and manage the Coronavirus Disease 2019 (COVID-19) reverse-transcription (RT)-qPCR is the gold standard molecular diagnostic method for COVID-19, mostly in automated testing platforms These systems are accurate and effective, but also costly, time-consuming, high-technological, infrastructure-dependent, and currently suffer from commercial reagent supply shortages The reverse-transcription loop-mediated isothermal amplification (RT-LAMP) can be used as an alternative testing method Here, we present a novel versatile (real-time and colorimetric) RT-LAMP for the simple (one-step), affordable (~17 €/sample), and rapid detection of SARS-CoV-2 targeting both ORF1ab and N genes of the novel virus genome We demonstrate the assay on RT-qPCR-positive clinical samples, obtaining most positive results under 25 min In addition, a novel 30-min one-step drying protocol has been developed to stabilize the RT-LAMP reaction mixtures, allowing them to be stored at room temperature functionally for up to two months, as predicted by the Q10 This Dry-RT-LAMP methodology is suitable for potentially ready-to-use COVID-19 diagnosis After further testing and validation, it could be easily applied both in developed and in low-income countries yielding rapid and reliable results