Development and validation of a rapid single-step reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) system potentially to be used for reliable and high-throughput screening of COVID-19

Minghua Jiang; Wenjie Fang; Amir Aratehfar; Xiaojing Li; Liyan ling; Hua Fang; Farnaz Farnaz Daneshnia; Jian Yu; Wanqing Liao; Hao Pei; Weihua Pan; Cornelia Lass-Florl

we considered the LOD of 500 copies/ml. Analytical specificity was 100% when used a wide range 151 of closely-and distantly-related viral species, prominent fungal and bacterial species, and human 152 DNA. Moreover, analytical evaluation included a wide range of inhibitors and 500 copies of the 153 simulated viral particles were successfully detected below 30 minutes (Figure 1) . In order to evaluate 154 the performance of our assay in clinic, we provided our assay and respective instructions to two 155 clinical centers (Figures 1, 2) . In total, 168 patients from center 1, among which 35 confirmed 156 COVID-19 cases, and 92 patients from center 2, among which 12 patients were confirmed COVID-157 19 cases, were recruited. One asymptomatic patient tested positive by qRT-PCR (Ct values 37) and 158 by our RT-LAMP was categorized suspected by in-charge physician and few days later became 159 positive. Four patients tested positive by qRT-PCR were negative by our RT-LAMP and one patient 160 tested negative by qRT-PCR was positive by our assay (Figure 1 and Supplementary Table 1) . 161