[Analytical performance evaluation of Flash10 point-of-care testing in severe acute respiratory syndrome coronavirus...

Objective: To evaluate the analytical performance of Flash10 point-of-care testing (POCT) in the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleic acid. Methods: The analytical performance evaluation of the Flash10 POCT system and its matching kits was carried out based on the non-infectious phage virus-like particles (VLPs) samples and inactivated viral culture samples. The limit of detection (LoD) was evaluated by testing gradient-diluted non-variant and Omicron variants (BA.5 and BF.7) VLPs samples and negative samples and using Probit regression analysis. The precision was evaluated by testing non-variant and Omicron variants (BA.5 and BF.7) VLPs samples with concentrations of 3 000.00, 1 000.00, 333.33 and 111.11 copies/ml and calculating coefficient of variation (CV) for cycle threshold (Ct) value of ORF1ab gene and N gene. The analytical specificity was evaluated by detecting 13 common respiratory pathogens that can cause symptoms similar to coronavirus disease 2019 (COVID-19). The testing ability of SARS-CoV-2 variants were assessed by detecting the VLPs samples with variants that have been prevalent worldwide (including Alpha, Beta, Delta, Omicron and so on). The sealing of this POCT system was evaluated by studying cross-contamination and the risk of contamination of nucleic acid amplification products. Results: The LoD of the Flash 10 POCT system for detecting non-variant samples and Omicron variant (BA.5, BF.7) samples were 92.97 copies/ml (95%CI: 63.68-196.27 copies/ml)、95.49 copies/ml (95%CI: 67.26-200.14 copies/ml) and 99.27 copies/ml (95%CI: 67.77-209.89 copies/ml), respectively, which aligned with the LoD (100 copies/ml) claimed by the reagent instructions. When detecting non-variant and Omicron variant (BA.5, BF.7) samples with four different concentrations, the CV of the Ct value of ORF1ab gene and N gene were 2.41% to 4.97% and 2.29% to 4.48%, respectively, which were all below 5%. The detection results of 13 common respiratory pathogens other than SARS-CoV-2 were all negative. The variants that have been prevalent worldwide can be correctly detected. The evaluation results of the risk of cross-contamination and nucleic acid amplification products contamination indicated that the Flash 10 POCT testing system was well sealed. Conclusion: The Flash10 POCT system demonstrates good analytical performance for SARS-CoV-2 nucleic acid detection.