[Enzyme-linked immunoabsorbent assay of factor VIII-related antigen. Interest in study of Von Willerbrand's disease (author's transl)].

Factor VIII-related antigen is measured by ELISA as follows: Factor VIII-R: Ag is first "captured" between rabbit antibodies to human factor VII R : Ag adsorbed in polystyrene tubes, and conjugate (peroxydase-labelled rabbit antibodies). A chromogenic enzyme substrate is then added and absorbence measurement allows subsequent assay. This method is sensitive, reproducible and specific. The comparison between the results obtained by this enzyme immuno-assay and the electro-immunodiffusion assay (EIA) is interesting for the study of quantitative and qualitative variations of F VII R : Ag in von Willebrand's disease. Two observations of von Willerbrand variants are described in detail : VIII R : Ag plasma level of the first one is normal using EIA but decreased using ELISA, its electrophoretic mobility is increased; in the second case we found typical anomalies of von Willebrand except the VIII R : Ag level normal by the two methods.