an in vitro binding assay in which an enzyme and its substrate (rather than a radioactive substance) serve as the indicator system; in positive test results, the two yield a colored or other easily recognizable substance; tests are made in wells in polystyrene or other material to which immunoglobulins or antigenic preparations readily adsorb; the enzyme is linked to known immunoglobulin (or antigen) and in positive test results remains in the well as part of the antigen-antibody complex available to react with its substrate when added.
