Enzyme-Linked Immunosorbent Assay
An enzyme linked immunosorbent assay (ELISA) is a heterogeneous enzyme immunoassay in which one of the reaction components (ligand or binder) is adsorbed nonspecifically to a solid phase surface. The analyte to be measured is added, followed by an enzyme labeled binder conjugate. This forms a sandwich complex of binder analyte conjugate or ligand analyte conjugate attached to the solid phase that can be measured when the enzyme substrate is added to the bound conjugate. The standard curve of an ELISA assay has a positive slope and is often asymmetrical.