A retrospective study of the relative utility of electrophoresis, immunoelectrophoresis, immunofixation, and nephelometry in the investigation of serum proteins

Objectives: To assess the relative value of visual inspection of protein electrophoresis patterns, immunoelectrophoresis, immunofixation, and specific protein quantitation in the investigation of serum proteins. Design and Methods: A retrospective study of protein results on 372 sera analyzed by electrophoresis and immunoelectrophoresis. A subsection of specimens (276) also had immunoglobulin quantitation by immunonephelometry and 30 were studied by immunofixation. Results: Total gamma globulin levels were correctly assessed visually in 84.4% of cases. Discrete bands seen visually were mainly monoclonal in 74 of 80 (92.5%). Six monoclonal proteins were not detected visually. Twenty-five monoclonal proteins required immunofixation for typing, and 60 were typed by immunoelectrophoresis. The visual assessment of the level of normal immunoglobulins in the presence of a monoclonal gammopathy was correct in 58% of cases. Conclusions: The majority of monoclonal gammopathies could be evaluated by a combination of protein electrophoresis and immunoelectrophoresis. Except for quantitating monoclonal immunoglobins, protein electrophoresis was unreliable as a quantitative procedure and nephelometry was preferred.