Diagnostic performance of routine electrophoresis and immunofixation for the detection of immunoglobulin paraproteins (M‐Proteins) in dogs with multiple myeloma and related disorders: Part 2—Toward improved diagnostic performance. (14th April 2021)

• Record Type: Journal Article
• Authors: Moore, A Russell; Harris, R. Adam; Jeffries, Christina; Ashton, Laura; Avery, Paul R.
• Is Part Of: Veterinary clinical pathology. Volume 50:Number 2(2021)
• Page Start: 249
• Page End: 258
• Publication Date: 2021-04-14
• Subjects: biclonal gammopathy -- canine -- Canis lupis familiaris -- ehrlichia -- immunotyping -- monoclonal gammopathy; Veterinary pathology -- Periodicals; 636.089607
• DOI: 10.1111/vcp.12940
• Languages: English
• ISSNs: 0275-6382

Abstract

Abstract: Background: The diagnostic performance of routine electrophoresis (agarose gel electrophoresis [AGE] and capillary zone electrophoresis [CZE]) and species‐specific immunofixation (IF) for the detection of immunoglobulin paraproteins (M‐proteins) and diagnosis of secretory myeloma‐related disorders (sMRD) can be improved. Available canine IF targets were IgG‐FC, IgA, IgM, light chain (LC), IgG4, and free LC (fLC) antibodies. Objective: We aimed to review specific features associated with the presence of M‐proteins in canine serum samples and the common features causing inaccurate reporting of M‐proteins to improve the diagnostic performance of routine electrophoresis and IF for the detection of M‐proteins. Methods: Features found in AGE, CZE, routine IF, IgG4 IF, and fLC IF of 100 canine serum samples from Part 1 of this study were evaluated by simple and multivariate logistic regression to identify factors associated with the presence of M‐proteins. Cases falsely called negative or positive for M‐proteins were reviewed to identify the common features that could be used to increase the diagnostic performance of SPE and IF for M‐protein detection. Results: The presence of hypogammaglobulinemia or any peak taller than albumin was associated with an M‐protein. Total protein concentrations, globulin concentrations, or peaks wider than albumin were not associated with an M‐protein. Free LC sMRD cases were not diagnosed by SPE and routine IF. Cases with infectious and inflammatory etiologies had a restricted polyclonal gammopathy with multiple γ‐globulin restrictions resulting in some false‐positive results. SPE combined with all available IF results and the specific features identified in this study had an estimated sensitivity of 95.1% and specificity of 81.4%. Conclusions: The identified criteria of this study increase the diagnostic performance of the electrophoretic evaluation for M‐proteins.