| IEP | Immunoelectrophoresis | (IEP) is a two-step procedure which first involves the electrophoretic separation of proteins, followed by the linear diffusion of antibodies into the electrophoretic gel from a trough which extends through the length of the gel adjacent to the electrophoretic path. The antigen-antibody reactions produce precipitin arcs at positions where equivalence occurs. Although quantitation is subjective, an experienced eye can determine not only the presence of the antigen but, through visual comparison to normal control sera, may discriminate relative increases or decreases of antigen by gauging the length and density of the precipitin arcs at positions established for specific antigens using known standards. |