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Antibody responses to SARS-CoV-2 in COVID-19 patients: the perspective application of serological tests in clinical practice

2020; Cold Spring Harbor Laboratory; Linguagem: Inglês

10.1101/2020.03.18.20038018

Quanxin Long, Haijun Deng, Juan Chen, Jieli Hu, Beizhong Liu, Pu Liao, Yong Lin, Lihua Yu, Zhan Mo, Yinyin Xu, Fang Gong, Guicheng Wu, Xian-xiang Zhang, Yaokai Chen, Zhijie Li, Kun Wang, Xiaoli Zhang, Wenguang Tian, Changchun Niu, Qingjun Yang, Jianglin Xiang, Hongxin Du, Huawen Liu, Chunhui Lang, Xiaohe Luo, Shaobo Wu, Xiaoping Cui, Zheng Zhou, Jing Wang, Chengjun Xue, Xiaofeng Li, Li Wang, Xiaojun Tang, Yong Zhang, Jingfu Qiu, Xia-mao Liu, Jin-Jing Li, Dechun Zhang, Fan Zhang, Xue-Fei Cai, Deqiang Wang, Yuan Hu, Ji‐Hua Ren, Ni Tang, Ping Liu, Qin Li, Ailong Huang,

SARS-CoV-2 detection and testing

Abstract Background We aim to investigate the profile of acute antibody response in COVID-19 patients, and provide proposals for the usage of antibody test in clinical practice. Methods A multi-center cross-section study (285 patients) and a single-center follow-up study (63 patients) were performed to investigate the feature of acute antibody response to SARS-CoV-2. A cohort of 52 COVID-19 suspects and 64 close contacts were enrolled to evaluate the potentiality of the antibody test. Results The positive rate for IgG reached 100% around 20 days after symptoms onset. The median day of seroconversion for both lgG and IgM was 13 days after symptoms onset. Seroconversion of IgM occurred at the same time, or earlier, or later than that of IgG. IgG levels in 100% patients (19/19) entered a platform within 6 days after seroconversion. The criteria of ‘IgG seroconversion’ and ‘> 4-fold increase in the IgG titers in sequential samples’ together diagnosed 82.9% (34/41) of the patients. Antibody test aided to confirm 4 patients with COVID-19 from 52 suspects who failed to be confirmed by RT-PCR and 7 patients from 148 close contacts with negative RT-PCR. Conclusion IgM and IgG should be detected simultaneously at the early phase of infection. The serological diagnosis criterion of seroconversion or the ‘>; 4-fold increase in the IgG titer’ is suitable for a majority of COVID-19 patients. Serologic test is helpful for the diagnosis of SARS-CoV-2 infection in suspects and close contacts.