Abstract:

Objective To investigate the clinical application value and diagnostic efficacy of severe acute respiratory syndrome coronavirus 2（SARS-CoV-2） antigen determination. Methods From March to June 2022，340 asymptomatic patients at the initial stage of corona virus disease 2019（COVID-19） in a shelter in Songjiang District，4 294 residents in a sealed control area，420 residents in a management control area and 800 residents in a prevention area were randomly enrolled for the determination of SARS-CoV-2 antigen. The positive SARS-CoV-2 antigen determination results were rechecked with double-reagent nucleic acid. Receiver operating characteristic（ROC） curve was used to evaluate the efficiency of SARS-CoV-2 antigen qualitative determination for the diagnosis of SARS-CoV-2 infection. Results The positive rate of SARS-CoV-2 antigen determination on the first day of shelter was 81.0%，and the average true positive rate of SARS-CoV-2 antigen determination in sealed control area and management control area was 43.1%. The positive rate of nucleic acid test was higher than that of SARS-CoV-2 antigen determination（P<0.01），and the consistency of the 2 methods was poor（Kappa value was 0.266）. The turn-to-negative time of SARS-CoV-2 antigen determination was earlier than that of nucleic acid test（P<0.05），and the antigen determination line （T line） did not show colour when the cycle threshold（Ct） value was >28. The area under curve was 0.773 for SARS-CoV-2 antigen determination. Conclusions Antigen determination can be used as an auxiliary method in the early screening of SARS-CoV-2，but it can not replace nucleic acid test.

Key words: Severe acute respiratory syndrome coronavirus 2, Antigen qualitative determination, Nucleic acid test, Diagnostic efficacy