A novel approach to the immunological stage of immunoblotting is described. The method employs the phenomenon of electroendosmosis to bring the antibodies sequentially into contact with the antigen. Using a three-stage peroxidase antiperoxidase system for human group specific protein (Gc) phenotyping, it has been shown that the method has comparable sensitivity, is more rapid and is more economical of antibodies than a similar multi-stage immerse-and-wash system.