Distortions but not Definitive Peaks by Capillary Serum Protein Electrophoresis Indicate Monoclonal Gammopathy of Undetermined Significance rather than Multiple Myeloma

Capillary electrophoresis of serum proteins demonstrates occasional distortions. Distortions or peaks in the gamma, beta, and alpha-2 zones may represent monoclonal gammopathy. In this study, we investigated if such distortions are associated with monoclonal gammopathy of undetermined significance (MGUS) or multiple myeloma. Consecutive serum protein electrophoresis results were reviewed and immunofixation studies were recommended on specimens exhibiting distortions or distinct peaks in the gamma, beta or alpha-2 zones. Of the 471 cases, we observed distortions in 101 cases. In the immunofixation studies, 17.8% of cases had a diagnosis of MGUS, but none contained multiple myeloma. We conclude that distortions in serum capillary electrophoresis may be associated with MGUS, but not multiple myeloma.