Diagnostic value of combined nucleic acid and antibody detection in suspected COVID-19 cases

Zeng, Huadong; Deng, Shaodong; Zhou, Zhou; Qiu, Xian; Jia, Xingwang; Li, Zhikui; Wang, Jun; Duan, Honglu; Tu, Li; Wang, Junli

Abstract Objectives Nucleic acid testing is the gold-standard method for the diagnosis of coronavirus disease 2019 (COVID-19); however, large numbers of false-negative results have been reported. In this study, nucleic acid detection and antibody detection (IgG and IgM) were combined in order to improve the testing accuracy of suspected COVID-19 patients. Study design xxxx Methods A total of 71 suspected COVID-19 patients were selected to participate in this study, which included a retrospective analysis of clinical features, imaging examination, laboratory biochemical examination, and nucleic acid detection and specific antibody (IgM and IgG) detection. Results The majority of participants with suspected COVID-19 presented with fever (67.61%) and cough (54.93%), and imaging results showed multiple small patches and ground-glass opacity in both lungs, with less common infiltration and consolidation opacity (23.94%). Routine blood tests were mostly normal (69.01%), while only a few patients had lymphopenia (4.23%) or leukopenia (12.68%). There was no statistical difference in the double-positive rate between nucleic acid detection (46.48%) and specific antibody (IgG and IgM) detection (42.25%) (P = 0.612); both of which were also poorly consistent with each other (Kappa = 0.231). The positive rate of combined nucleic acid detection and antibody detection (63.38%) was significantly increased, compared with that of nucleic acid detection (46.48%) and that of specific antibody (IgG and IgM) detection (42.25%), and the differences were statistically significant (P = 0.043 and P = 0.012, respectively). Conclusions Nucleic acid detection and specific antibody (IgG and IgM) detection had similar positive rates, and their combination could improve the positive rate of COVID-19 detection, which is of great significance for diagnosis and epidemic control.