Development of a SARS‐CoV‐2 rapid antibody detection kit and study on dynamic changes in antibodies in infected patients

Wang, Huihui; Li, Xuemei; Li, Tao; Wang, Lianzi; Wang, Li; Lin, Jiawang; Zhang, Shubing; Xu, Yuanhong; Wei, Wei

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) has spread rapidly to 185 regions and countries around the world with more than 2.8 million confirmed infections and 203,044 deaths. Respiratory diseases caused by SARS‐CoV‐2 are serious threats to human health. OBJECTIVES: To develop a rapid detection kit for new coronavirus antibodies and use it to study the dynamic changes in antibodies in clinically confirmed SARS‐CoV‐2‐infected patients. METHODS: The SARS‐CoV‐2 IgM/IgG antibody test kit (colloidal gold method) was developed. Serum SARS‐CoV‐2 IgM and IgG antibodies were tested in SARS‐CoV‐2‐ and non‐SARS‐CoV‐2‐infected persons, respectively. RESULTS AND CONCLUSION: The sensitivities of the SARS‐CoV‐2 IgM/IgG antibody test kit (colloidal gold method) were 50%, 70%, 92.5% and 97.5% after 1–3 days, 4–6 days, 7–9 days and >9 days of admission, respectively, and the specificities of the IgM, IgG and IgM + IgG antibodies were all 100%. Using the SARS‐CoV‐2 IgM/IgG antibody test kit (colloidal gold method), the positive rates of SARS‐CoV‐2 IgM and IgG antibodies increased from 50% to 92.5% after 1–3 days, 4–6 days and 7–9 days of admission, which showed an increasing trend. The titers of the SARS‐CoV‐2 IgM and IgG antibodies in the positive specimens increased with the length of admission.