When the SARS-CoV-2 IgM test was carried out for all control serum and serum from COVID-19 patients by GICA and ELISA, the results showed that false-positive interference occurred only in RF-IgM-positive serum, and the serum results from COVID-19 patients were all positive, indicating that the two methods had high sensitivity but that their specificity needed to be improved. This evidence concerns the gene CD40LG and COVID-19.