Utility of immunofixation in complementing and empowering serum protein electrophoresis in the diagnosis of paraproteinemia: Experience at a tertiary care center

Abstract

Background: ‘M’ proteins or paraproteins refer to immunoglobulins that are produced by clonal plasma cells and are a characteristic feature of monoclonal gammopathies. Routine electrophoresis on agarose gel and immunofixation can be used to detect immunoglobulin paraprotein (M-protein). We aimed to evaluate the performance of agarose gel electrophoresis alone and in combination with immunofixation for detecting serum M-proteins. Methods: One hundred and twenty-three patients suspected of paraproteinemia were evaluated. Routine serum protein electrophoresis (SPE) and immunofixation electrophoresis (IFE) protocols were performed. Data from SPE, and SPE-IFE (gel images and electrophoretograms) were collected and reviewed. Results: 21% cases were confirmed using the SPE-IFE combination, and among them, 33% had positive light chain (λ) only on IFE. Similarly, nine cases with biclonal gammopathy on SPE were characterized by IFE. Conclusion: IFE can be a confirmatory test in cases where SPE results are not reliable and it can be a complementary test when characterization of the M protein detected on SPE is required.

Keywords

• paraproteins
• blood protein electrophoresis
• m-protein