Lab Med Online.  2022 Apr;12(2):122-128. 10.47429/lmo.2022.12.2.122.

External Quality Assessment of Serum Protein and Immunofixation Electrophoresis in Korea

• Cho J
• Lee DH
• Rim JH
• Lee SG

• KMID: 2538595
• DOI: http://doi.org/10.47429/lmo.2022.12.2.122

Abstract

In Korea, many laboratories rely on inter-laboratory proficiency testing for external quality control of serum protein electrophoresis (SPEP) and immunofixation electrophoresis (IFE). Therefore, we conducted an external quality assessment in 12 clinical laboratories. Five test samples were prepared by pooling residual samples together in our laboratory according to the SPEP pattern or the existence of monoclonal proteins, and then aliquoting them. Each clinical laboratory carried out SPEP and IFE tests, quantified each fraction and monoclonal protein (if present), and produced the interpretation reports according to the method of each laboratory. Monoclonal protein was detected in two of the five test samples, and the detection of monoclonal proteins and the isotyping results were consistent in all participating institutions. There were no significant variations in the quantities of albumin, alpha-1, and -2 globulin fractions, and the whole beta-gamma region. However, the values of beta-1, -2, and gamma globulin fractions differed significantly, and there was a large variation in the reported monoclonal protein concentrations. The quantitative values obtained using the tangent skimming method were much lower than those obtained using the other methods. In this study, the interpretation reports were generally consistent, but the quantitative values were different between the participating laboratories. This is the first study to approach the external quality assessment of SPEP and IFE in Korea. Further studies are required to establish external quality control management for these tests.

Keyword

Serum protein electrophoresis; Immunofixation electrophoresis; Quantitation; Monoclonal protein; External quality assessment

Figure

• 

  Fig. 1 Serum protein electrophoresis (SPEP) (left) and immunofixation electrophoresis (IFE) (right) profiles of five samples. The serum electrophoresis patterns displayed in this figure were demonstrated by the Capillarys 2 Flex Piercing analyzer (Sebia, Lisses, France). Monoclonal protein was detected in two of the five test samples (samples 1 and 4), and the detection of monoclonal proteins and the isotyping results (Immunoglobulin (Ig) G kappa type for sample 1 and IgA lambda type for sample 4) were consistent in all participating laboratories.

• 

  Fig. 2 Number of participating laboratories according to the quantitation method for monoclonal protein in sample 1 (A) and sample 4 (B). Abbreviation: M protein, monoclonal protein.

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