(61a) A Rapid, Accurate, Scalable and Portable Testing (SPOT) System for COVID-19 Diagnosis

The pandemic caused by SARS-CoV-2 has brought tremendous pressure on public health systems all over the world. With the unceasing emergence of viral mutants, a method for rapid and multiplex viral detection is in high demand. Here we report a rapid Scalable and Portable Testing (SPOT) system consisting of a rapid, highly sensitive, and accurate assay and a battery-powered portable device for COVID-19 diagnosis. The SPOT assay comprises a one-pot reverse transcriptase-loop-mediated isothermal amplification (RT-LAMP) followed by PfAgo-based target sequence detection. It was capable of detecting as low as 7.5 copies/reaction (0.38 copies/µL) of in vitro transcribed SARS-CoV-2 RNA and the N gene and E gene in a multiplexed reaction with the limit of detection (LoD) of 17.5 copies/reaction (0.44 copies/µL) and 43.8 copies/reaction (1.09 copies/µL), respectively, in SARS-CoV-2 virus-spiked saliva samples within 30 min. Moreover, the SPOT system was used to analyze 104 clinical saliva samples and identified 28/30 (93.3% sensitivity) SARS-CoV-2 positive samples (100% sensitivity if LoD is considered) and 73/74 (98.6% specificity) SARS-CoV-2 negative samples. This combination of speed, accuracy, sensitivity, and portability will enable high-volume low-cost access to areas in need of urgent COVID-19 testing capabilities. In addition, the SPOT system presented here enables rapid diagnosis without trained personnel and only minimal liquid handling, thus endowing this system the ability as an at-home diagnostic tool.