Optical density results of serum samples in the newly developed indirect IgG PCV2 Cap VLP-based ELISA. Four hundred and nine serum samples previously characterized by the commercial SERELISA test were analyzed by the newly developed indirect PCV2-Cap VLP IgG ELISA. The absorbance at 450 nm obtained for the serum samples are shown. The dotted line indicates the assay cut-off, which was established to be 0.3. for the indirect PCV2 Cap VLP IgG ELISA. Opened circles represent discrepant results, filled circles indicate matching results with commercial SERELISA test. ID sera, serum sample number.