Abstract: Objective To conduct the quantitative analysis of SARS-CoV-2 nucleic acid detection sensitivity loss, and to provide support for improving the detection process and solving the false negative problem. Methods The N gene pseudovirus was taken as the sample, the factors that might affect the diagnostic sensitivity in nucleic acid extraction method, pH of preservation solution, volume of preservation solution used for nucleic acid extraction were analyzed and optimized systematically, and the optimized detection method was compared with the current conventional detection method. Results The detection sensitivity could be improved by extraction of nucleic acid by centrifugal column method and using acid sample preservation solution. With the increase of the volume of the preservation solution, the pseudovirus was released more fully. When the volume of the preservation solution reached 3 mL, the pseudovirus was almost completely eluted. The detection sensitivity exhibited more than ten times the difference when 200 μL and 3 mL preservation solution were used to extract nucleic acid, respectively. When the whole preservation samples was extracted by centrifugal column method, and 12 μL template was added into the PCR system, the detection sensitivity could reach 70 copies/mL; when 200 μL preservation sample was taken to extract the nucleic acid, and 4 μL template was added into the PCR system, the detection sensitivity was 700 copies/mL. Conclusion The novel coronavirus specimens are stored in the slightly acidic sample, and the nucleic acid is extracted by centrifugation column method using as many preservation solution samples as possible, and the largest number of nucleic acid templates are added into the PCR system. The sensitivity of the nucleic acid detection method is 10 times higher than that of the conventional detection method.

Key words: SARS-CoV-2, Nucleic acid detection, Reverse transcription-polymerase chain reaction, False negative