Evaluation of recombinant nucleocapsid and spike proteins for serological diagnosis of novel coronavirus disease 2019 (COVID-19)

Pingping Zhang; Qi Gao; Tang Wang; Yuehua Ke; Fei Mo; Ruizhong Jia; Wanbing Liu; Lei Liu; Shangen Zheng; Yuzhen Liu; Luping Li; Yao Wang; Lei Xu; Kun Hao; Ruifu Yang; Shiyue Li; Changqing Lin; Yong Zhao

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.17.20036954 doi: medRxiv preprint or they were not normally modified. Thus, the N protein's antigenicity should be 1 studied after expression in a eukaryotic system in future. 2 GICA, a simple and rapid serological method, is especially suitable for timely 3 diagnosis and large-scale sample screening. A recent study showed that the sensitivity 4 of the total antibody (IgM and IgG) test is higher than that of the IgM or IgG test [16] . 5 Therefore, we developed a sandwich-format GICA with rS1 and rS-RBD-mFc to 6 detect total antibodies in patient serum. The GICA tests were highly sensitive 7 (86.89%) and specific (99.39%), which should help with diagnosing COVID-19 in 8 RT-PCR-negative patients who are clinically confirmed COVID-19 positive by CT. 9