The Detection by Immunofixation Electrophoresis (IFE) of Monoclonal Proteins in Veteran Patients with Hypogammaglobulinemia on Negative Serum Protein Electrophoresis, the Veteran Affairs Medical Center (VAMC) Experience

Abstract Introduction/Objective Serum protein electrophoresis (SPEP) is the backbone laboratory test for the detection of abnormal monoclonal proteins. However, IFE is a sensitive assay that can sometimes detect monoclonal proteins even when the corresponding SPEP is negative. The fact that IFE is more sensitive than SPEP combined with the need to avoid overutilization of IFE has led to published algorithms for guidance. Hypogammaglobulinemia in a new patient has been recognized in these algorithms as a reason to reflex to IFE when SPEP is negative, though studies on veteran patients are sparse. Therefore, this QA study of the percentage of positive IFEs in negative new SPEP veteran patients with hypogammaglobulinemia was undertaken to ensure reflex IFEs would still be indicated. Methods As part of a quality assurance/quality improvement project, a retrospective Vista/Fileman search of all SPEPs with IFE performed from January 2017 to February 2019 was undertaken to identify cases of SPEPs showing hypogammaglobulinemia (<0.7 g/dL). Diagnostic comments were then analyzed to identify cases of hypogammaglobulinemia along with the M-spike (<0.1 g/dL) to identify negative SPEPs. Only those cases that were consistent with first time hypogammaglobulinemia without an obvious M-spike were included and tabulated for calculations. Any result that was not negative for a monoclonal band was considered as positive. Results There were a total of 194 specimens that met the criteria of SPEP with hypogammaglobulinemia and standard comments consistent with first time analysis and without an obvious M-spike on SPEP. Out of these 194 specimens, 45 had a positive result, either as a monoclonal band comigrating with the beta protein peak or as a very faint gamma or beta monoclonal band. This represented approximately 23% of the specimens, about double the literature published rate for the non-veteran population. Conclusion The performance of IFE on new hypogammaglobulinemia veteran patients appears to be indicated like previously published algorithms and is supported by the fact that about double (23%), compared to the non-veteran population, had positive IFEs despite negative SPEPs. IFE is a helpful tool for new hypogammaglobulinemia patients for the detection of monoclonal proteins despite negative SPEPs.