System design and clinical validation of intelligent nucleic acid POCT for un SARS-CoV-2 detection within 30 min

Rapid and accurate point-of-care-test (POCT) allows us to substantially accelerate taking clinical decisions and implement strategic planning at the national level of preventative measures in epidemic prevention and control. Here, we report Intelligent Nucleic Acid Test (iNAT) for the RT-qPCR detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA with a limit of detection (LOD) of 22.4 copies/mL. iNAT is a sample-to-answer system consisting of an instrument and a fully enclosed detection chip containing reaction reagents, based on rotary valve liquid control technology, ultrasonic-assisted nucleic acid extraction (NAE) technology, thin-sheet rapid PCR technology, freeze-drying technology, liquid transfer, NAE and RT-qPCR are all completed automatically, quickly and efficiently, and free of cold chain transportation and storage. The user only needs to put the chip with 160 uL sample into the instrument and click to start, the test result will report after 30 min. In a clinical trial between the iNAT and the traditional RT-qPCR kits approved by National Medical Products Administration (NMPA), involving 158 throat swab samples, the concordance rate reached 96.2%, the positive percent agreement (PPA) is 95.8%, and the negative percent agreement (NPA) is 97.3%, the parallel analysis of Ct values of 115 positive samples was a high correlation (R2=0.95), 4 of 10 weak positive samples were missed by iNAT while 6 of 10 weak positive samples were missed by reference kits. In a word, iNAT system provide an ultra-high sensitivity and fast POCT detection method for SARS-CoV-2.