Characterization of an enzyme immunoassay by means of specific interaction affinities

Antigen--antibody interactions involved in an enzyme immunoassay are characterized by their specific affinities. The use of a nonlinear least-squares approach of the response versus dose dependence allows the extrapolation of experimental data, as well as qualitative and/or quantitative assumptions about the interactions studied. As a practical test, the present technique has important advantages over common titration methods, by avoiding the fixation of a cut-off limit for positive and negative samples and by determining the affinity of the specific interaction for any dose required.