CD40LG and COVID-19: Of the 20 FDA-EUA LFIs that detect IgM and/or IgG against SARS-CoV-2, only three LFIs were designed for the sole detection of IgG (RapCov Rapid COVID-19 Test [48], SCoV Detect IgG Rapid Test [49] and SGTi-flex COVID-19 IgG [50]) whereas the rest incorporate the detection of both IgM and IgG (Table 3).