Peaks and tails: Evaluation of irregularities in capillary serum protein electrophoresis

The increased analytical sensitivity of capillary electrophoresis detects additional irregularities that are suspicious for a monoclonal component. This is most noticeable in the beta-1-, beta-2- and gamma-globulin fractions. The causes of non-monoclonal irregularities are manifold, but are rarely reported back to the ordering physician. This article reviews the basic concepts to correctly identify irregularities, monoclonal and oligoclonal peaks by capillary electrophoresis. It then focuses on detecting and reporting typical non-monoclonal irregularities according to their electrophoresis fractions as well as their possible clinical implications. •We review basic concepts to recognize irregularities, monoclonal and oligoclonal peaks in serum capillary electrophoresis•The focus is on the origin of pseudo-monoclonal irregularities•The corresponding electrophoresis patterns are reviewed and graphically presented.