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

OBJECTIVE: 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. METHODS: 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. RESULTS AND DISCUSSION: 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. CONCLUSIONS: We conclude that distortions in serum capillary electrophoresis may be associated with MGUS, but not multiple myeloma.