Chemiluminescence-linked immunoassay.

Covalent complexes of a chemiluminescent compound (a luminol derivative), protein and a steroidal hapten have been used as a labelled antigen in a way analogous to the radioactive label in radioimmunoassay. The antibody-bound complex emits light when treated with hydrogen peroxide and copper acetate at high pH. The chemiluminescent complex bound to antibody can be displaced by free steroid to produce a standard curve in a way analogous to radioimmunoassay.