The ELISA assay is based on the competitive principle. Each well of the supplied microtiter plate has been pre-coated with recombinant SARS-CoV-2 Spike RBD-hFc protein. When HRP conjugated recombinant human ACE2 protein is added simultaneously to wells along with diluted human serum/plasma samples, immobilized RBD will bind human ACE2 protein. Binding of RBD to human ACE2 protein is dose-dependently inhibited by presence of anti-SARS-CoV-2 human neutralization antibodies in serum samples. Following the sample incubation step, unbound ACE2-HRP conjugate is washed away. A Positive Control is a known human antibody (IgG1 subtype) which is specific for SARS-CoV-2 spike protein with a binding epitope for RBD binding site. The positive control antibody is validated by an established pseudovirus infection of cultured human cells for proven neutralization function. A human IgG1 isotype control is used as a Negative Control sample. The absorbance of unknown sample can then be compared to the Positive and Negative controls to determine absence or presence of anti-SARS-CoV-2 human neutralization antibodies. In the competition assay, the greater the amount of anti-SARS CoV-2 human neutralization antibodies in the sample, the lower the color development and optical density reading. 
 
Specificity: This kit is for the detection of Human anti-SARS-CoV-2 neutralization antibodies. 
Sample Types: This kit is recommended for use with human serum/plasma.  Use with other sample types like SARS-CoV-2 immunized animal serum is possible but not validated in this testing kit.
Detection Range: 10 to 500 ng/ml using positive control antibody 8A5
Sensitivity: typically, about 7.0 ng/mL with IC50 at approximately 50.0 ng/mL
Performance: Intra-Assay CV (< 10.0%); Inter-Assay CV (< 15.0%)
Limitations: This kit is for Research Use Only.