Clinical evaluation and application of detection of IgM and IgG antibodies against SARS-CoV-2 using a colloidal gold immunochromatography assay

ABSTRACT

The pandemic of the novel coronavirus (SARS-CoV-2) infection has seriously threated global public health, a rapid and easy operated method for coronavirus disease (COVID-19) diagnosis is needed. To evaluate the clinical application efficacy of the colloidal gold rapid test kit for detection of the IgM/IgG antibodies to SARS-CoV-2, a total of 304 clinical diagnosed case, 138 health donor (of which 114 showed SARS-CoV-2) viral RNA negative and 64 other fever patients with respiratory symptoms were selected for the study and the plasma or serum samples were tested for both IgM and IgG with the kit. The comparison of the detection coincidence of the samples from whole blood and plasma or serum were also performed;Furthermore, the time distribution of SARS-CoV-2 viral RNA and IgM/IgG antibodies detections were analyzed. The results showed that, of the 304 clinical diagnosed cases, 105 cases were positive for viral RNA detection, among which the detection sensitivity of IgM and IgG antibodies to SARS-CoV-2 by colloidal gold rapid assay was 76.2% (80/105) and 86.6% (91/105), respectively, and the overall coincidence rate of IgM/IgG antibody was 96.1% (101/105);and 73 cases were negative for both nucleic acid and antibody detection. Of the remaining 126 clinical diagnosed cases, the positive rate of IgM and IgG was 69.2% (87/126) and 98.3% (125/126), respectively, and the overall coincidence rate of IgM/IgG antibody was 100% (126/126). In detections for healthy and other fever patients, the specificity of IgM and IgG was 99% (200/202) and 98% (198/202), respectively, and the total coincidence rate of antibody detection results of homologous whole blood and plasma samples was 99%, indicating a high degree of consistency. In this study, the detection assay of SARS-CoV-2 antibodies using colloidal gold method showed satisfactory detection effect, and it could be used for clinical auxiliary diagnosis and epidemiological investigation, which could be applied in a wide range of scenarios and play a valuable role in the prevention and control of SARS-CoV-2 pandemic.