Diagnostic performance of routine electrophoresis and immunofixation for the detection of immunoglobulin paraproteins (M‐Proteins) in dogs with multiple myeloma and related disorders: Part 1 – Current performance. (13th 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: 240
• Page End: 248
• Publication Date: 2021-04-13
• Subjects: biclonal gammopathy -- canine -- Canis lupis familiaris -- Ehrlichia -- immunotyping -- monoclonal gammopathy; Veterinary pathology -- Periodicals; 636.089607
• DOI: 10.1111/vcp.12993
• Languages: English
• ISSNs: 0275-6382

Abstract

Abstract: Background: Routine electrophoresis [agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE)] and species‐specific immunofixation (IF) can be used alone or in combination to detect immunoglobulin paraprotein (M‐protein) and diagnose secretory myeloma‐related disorders (sMRD). Objective: We aimed to evaluate the performance of AGE, CZE, CZE plus IF (CZE‐IF), and AGE plus IF (AGE‐IF) for detecting canine serum M‐proteins. Methods: One hundred canine cases that had AGE, CZE, and routine IF performed on serum, and where B‐cell lineage neoplasia (such as B‐cell lymphoma and plasma cell tumors) had been diagnosed or excluded, were evaluated. Routine IF protocols targeted IgG‐FC, IgA, and IgM heavy chains and light chains. IgG4 IF and free light chain IF were also performed. B‐cell lineage neoplasms with an M‐protein detected, using any available method, were classified as sMRD. Datasets from AGE, CZE, IF, CZE‐IF, and AGE‐IF (electrophoretograms, gel images, and fraction concentrations) were composed and reviewed. The sensitivity, specificity, and Youden's index for M‐protein detection were determined for each dataset. Results: The combination of AGE‐IF or CZE‐IF was more sensitive (82.9%) than CZE alone (72.0%) or AGE alone (64.6%) and more specific (66.1%, 48.3%, 51.7%, respectively). Immunofixation could be used alone to detect M‐proteins (sensitivity 82.9%, specificity 61.9%), but there were technical challenges that complicated the performance and evaluation of the test. Myeloma with free light chains only was found in 5/41 cases of sMRD. Conclusions: Adding routine IF to routine electrophoresis increases the ability to accurately identify M‐proteins; however, there is still room for further diagnostic performance improvements.