The specificity of the LFIAs ranged from 90.0% (95% CI: 82.2–94.59) to 99.0% (95% CI: 93.03–99.86) for IgM, from 92.0% (95% CI: 84.65–96.00) to 96.0% (95CI: 89.66–98.52) for IgG, and from 87.0% (95% CI: 78.72–92.37) to 96.0% (95% CI: 89.66–98.52) for IgM or IgG antibodies in RT-PCR negative specimens that were drawn during COVID-19 pandemic. This evidence concerns the gene CD40LG and COVID-19.