Although in this review, only 5 of the 18 serological RDT kits offered combined IgM and IgG detection, we also found a better performance characteristic for this type of RDT kit compared to the antigen and total immunoglobulin kits using non-colloidal gold labelling system with acceptable sensitivity (98% – 100%) and a specificity (98% – 99%) values for IgG and specificity of 96% – 99% for IgM, suggesting the ability of these kits to detect past infections, confirm true negative results and rule out false positive COVID-19 testing results by RT-PCR. The gene discussed is CD40LG; the disease is COVID-19.