ABSTRACT
To determine if a method to detect antibodies against SARS-CoV-2 can be applied clinically. In this retrospective study, the sera samples of 39 patients with newly diagnosed coronavirus disease 2019 (COVID- 19) and 90 healthy people were analyzed by antibody-detection reagents within enzyme-linked immunosorbent assays. The sera samples of confirmed cases at different onset times and 40 suspected cases were also tested. Then. we combined the results of antibody tests. nucleic-acid tests, and patient data. The sensitivity and specificity for SARS-COV-2-specific total antibodies was 92.31% and 100%, respectively. The production time of total antibodies in serum samples increased with time. and the median detection time was 13 days. The result of antibody testing of one confirmed case preceded the result of the nucleic-acid test. Moreover, the antibodies 0f 40 suspected cases were all negative. Detection of the total antibodies against SARS-CoV-2 can be used as an auxiliary diagnostic indicator of infection by this virus, as well as a supplementary means to exclude suspected cases/populations in areas with a high prevalence of negative detection of the nucleic acids of SARS-CoV-2.