HAI is closely related to HA analysis, mainly through antiviral antibodies as "inhibitors" that interfere with the interaction of viruses and RBCs. The purpose is to characterize the concentration of antibodies in antiserum or other samples containing antibodies. HAI assay is usually performed by creating antiserum dilutions serially in each well of a 96-well microtiter plate. A standard amount of virus or bacteria will be added to each well, and the mixture will be incubated at room temperature. It is necessary to set up a negative control without adding virus for each sample. During the incubation, the antibody will bind to the virus particles. If the antibody concentration and its binding affinity are sufficiently high, the blood coagulation reaction can be effectively blocked. https://antiviral.creative-diagnostics.com/hemagglutination-inhibition-assay-hai.html