Chemi-Luminescence ImmunoAssay (CLIA) for the quantitative determination of antibodies to COVID-19 Virus (SARS-CoV-2) Spike antigens in human plasma and sera. The Antibody assay is intended for testing: (a) health-care workers at risk of COVID-19 infection to verify whether or not they might be positive for potentially neutralizing anti Spike antibodies. (b) normal population for epidemiology studies on presence of potential “protective” Antibodies to SARS-CoV-2 Spike antigens; (c) PCR-negative infected individuals, successfully recovered from infection, to assure presence of potentially neutralizing antibodies; (d) human donors, recovered from COVID-19 infection, positive for anti-Spike I Antibodies for the generation of hyperimmune plasma, as a possible immunotherapeutic approach to the disease; (e) vaccinated individuals to assure a reliable positive immunization with development of anti Spike Antibodies antibodies.