CD40LG and COVID-19: The comparison between MAGLUMI 2019-nCoV positive/negative versus BIOSYNEX COVID-19 BSS positive/negative results yielded an overall concordance of 86% for both IgM and IgG detection, with a Cohen’s kappa coefficient of 0.71 (95%CI: 0.54-0.87) for IgG and 0.71 (95%CI: 0.54-0.87) for IgM.