The characteristic wavy band is recognized exclusively in association with IgG-myeloma protein. The pseudo-wavy band is also seen in some cases of IgG-myeloma, as well as IgA-myeloma, macroglobulinemia, IgG-benign monoclonal gammopathy and hypergammaglobulinemia such as liver cirrhosis, chronic thyroiditis, renal cell carcinoma and reticulum cell sarcoma.
Formation of the wavy band depends on both the nature of the abnormal globulin involved and the property of the supporting medium used. The more the reduced specific viscosity of the abnormal globulin, the more the tendency of forming the wavy band. In addition, the pores in the supporting medium should be small and irregular in their size, in order to develop the characteristic wavy band. It is most characteristically demonstrated on Oxoid and Separax membranes. Among other cellulose acetate membranes, Millipore and Sepraphore III membranes have the least tendency to form the wavy band.