This kit is comprised by HRP conjugate, other auxiliary reagents, ELISA Microtiter plate pre-coated with FMD-A antigen. Apply the principle of enzyme-linked immunoassay (ELISA) to detect FMD-A antibody in serum and plasma of cattle, goat, sheep. During the experiment, add control serum and samples into the ELISA Microtiter plate. If FMD-A antibodies exist in the samples, it will compete with the antibody in the antibody working solution to bind with the antigen pre-coated on the Microplate. Then wash the plate to remove unbound antibodies and other components, add the HRP conjugate to specifically bind with the compound of antibody and antigen on the microtiter plate. The unbound HRP conjugate will be removed by washing. Substrate Reagent is added into the well, it will react with the enzyme and become blue. The color shade is negative correlation with FMD-A antibody levels in the samples. At last, end the reaction by adding stop solution to produce a yellow product. Measure the absorbance value of each well by using a Microplate Reader with 450 nm wavelength, then we can know whether there are FMD-Aantibodies in the samples.