Finally, of the 24 patients with RT-PCR negative but considered COVID-19 probable cases, 11 (45.8%) were IgG positive with LFIA, 12 (50%) with CLIA-iFlash, 10 (41.6%) with CLIA-LIAISON® XL, and 11 (45.8%) with ECLIA-Elecsys®, while 6 (25%) and 7 (29.2%) were IgM positive with LFIA and CLIA-iFlash, respectively, and 10 (41.6%) with ELISA IgA. The gene discussed is CD40LG; the disease is COVID-19.