Direct ELISA vs. Competitive ELISA
In direct ELISA, antibody from serum is added to solid support containing antigen, then enzyme or secondary antibody is added and O.D measured using a standard curve.
In competitive ELISA, antibody from serum is added to support containing antigen, then radiolabeled antibody is added. if radiolabeled antibody binds, it means that original serum did not contain antibody. standar curve also used