Diagnostic value and dynamic variance of serum antibody in coronavirus disease 2019

• Main Authors: Yujiao Jin, Miaochan Wang, Zhongbao Zuo, Chaoming Fan, Fei Ye, Zhaobin Cai, Ying Wang, Huaizhong Cui, Kenu Pan, Aifang Xu
• Format: Article
• Language: English
• Published: Elsevier 2020-05-01
• Series: International Journal of Infectious Diseases
• Subjects: COVID-19; SARS-CoV-2; Diagnosis; Serological test; Immunoglobulin M; Immunoglobulin G
• Online Access: http://www.sciencedirect.com/science/article/pii/S1201971220301983

Objective: To investigate the diagnostic value of serological testing and dynamic variance of serum antibody in coronavirus disease 2019 (COVID-19). Methods: This study retrospectively included 43 patients with a laboratory-confirmed infection and 33 patients with a suspected infection, in whom the disease was eventually excluded. The IgM/IgG titer of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was measured by chemiluminescence immunoassay analysis. Results: Compared to molecular detection, the sensitivities of serum IgM and IgG antibodies to diagnose COVID-19 were 48.1% and 88.9%, and the specificities were 100% and 90.9%, respectively.In the COVID-19 group, the IgM-positive rate increased slightly at first and then decreased over time; in contrast, the IgG-positive rate increased to 100% and was higher than IgM at all times. The IgM-positive rate and titer were not significantly different before and after conversion to virus-negative. The IgG-positive rate was up to 90% and not significantly different before and after conversion to virus-negative. However, the median IgG titer after conversion to virus-negative was double that before, and the difference was significant. Conclusions: Viral serological testing is an effective means of diagnosis for SARS-CoV-2 infection. The positive rate and titer variance of IgG are higher than those of IgM in COVID-19.