Rapid Molecular Detection of SARS-CoV-2 (COVID-19) Virus RNA Using Colorimetric LAMP

Yinhua Zhang; Nelson Odiwuor; Jin Xiong; Luo Sun; Raphael Ohuru Nyaruaba; Hongping Wei; Nathan A Tanner

The emergence of a new coronavirus (2019-nCoV, now named SARS-CoV-2) has infected tens of thousands of people in China, with cases in at least 28 other countries and prompting a worldwide response. The diagnostics industry has responded rapidly, with Emergency Use Authorization granted for PCR-based tests from the US CDC (https://www.cdc.gov/coronavirus/2019-ncov/about/testing.html), Seegene in Korea and BGI in China (https://www.bgi.com/global/company/news/bgi-develops-realtime-dna-based-kit-for-detecting-the-2019-novel-coronavirus/) among many other providers releasing reagents, primers and probes, and other materials to support this urgent public health need. The current diagnostic standard combines clinical symptoms and molecular method, and as many of the symptoms resembles those of common cold and influenza, an accurate molecular result is critical for final diagnosis. These molecular methods include metagenomics sequencing mNGS (1) and RT-qPCR(2), both are excellent and sensitive techniques, but approaches not without limitations. mNGS is restricted by throughput, turnover time, formidable high cost and requirement for high technical expertise. As with most molecular diagnostics, RT-qPCR is the most widely used method, but it requires expensive laboratory instruments and is difficult to utilize outside of well-equipped facilities. In combination to the different patient samples containing variable number of virus, a high proportion of patients were diagnosed as false negatives (3, 4) .