Our study showed that, majority of COVID-19 patients (92.6%) who were reactive for SARS-CoV-2 IgM antibody had PCR CT< 30 and this key finding confirmed that antibody test can also be used as diagnostic and surveillance tool to assist screening of COVID-19 to provide vital information on the spread of the disease and to forecast future hotspots areas. This evidence concerns the gene CD40LG and COVID-19.