[Comparison of diagnostic values of immunoelectrophoresis and other methods of determination of the class and type of M protein].

Comparative analysis of immunoelectrophoresis (IEF) and several other laboratory methods used in the diagnosis of protein M showed that IEF is a method of choice in the immunological characterization of this protein, with the exception of IgM macroglobulin where the interpretation of the heavy chain and particularly of the light chain give better results in dilution immunodiffusion or immunochromatography. When the results are uncertain the simplest additional method to IEF seems to be dilution immunodiffusion and the best method is isolation of the observed protein by column chromatography and repeated determination of purified protein by IEF. With all these methods the lambda type of protein M is more difficult to determine than the kappa type.