This kit is comprised by HRP conjugate, other reagents and ELISA Microtiter plate pre-coated with recombinant cap protein of porcine circovirus Ⅱ (PCV2). Apply the principle of enzyme-linked immunoassay (ELISA) to detect PCV2-Ab in serum of porcine. During the experiment, add control and samples into the ELISA Microtiter plate, PCV2-Ab will be bound with the antigen on the ELISA Microtiter plate. Then wash the plate to remove unbound components, horseradish peroxidase (HRP) conjugate is added to each ELISA Microtiter plate well. The unbound HRP Conjugate will be removed by washing and substrate reagent is added for color development. At last, end the reaction by adding Stop Solution to produce a yellow product. There is a positive correlation between the OD value of samples and the concentration of PCV2-Ab. Measure the absorbance value of each well by using a microplate reader with 450 nm (630 nm) wavelength, then we can judge whether PCV2 antibody exist in the sample.