Fix-IT! Utilizing all your tools for challenging Immunofixation and Immunotyping test results

Abstract
Current guidelines by the International Myeloma Working Group and College of American Pathologists recommend performing serum protein electrophoresis (SPEP) and serum free light chain (sFLC) testing as a first-line assessment of potential disease. In cases where abnormalities are detected, follow-up testing by immunofixation (IFE) or an equivalent diagnostic method are recommended. Immunosubtraction, also called immunotyping (IT), is an equivalent diagnostic method for the isotyping of monoclonal proteins in serum. However, due to the technical differences between each method, IT has several unique advantages for overcoming technical challenges, including the presence of monoclonal proteins within polyclonal background immunoglobulins, overlapping monoclonal protein bands, or ambiguous migration patterns. The following presentation will highlight the complementary use of both IFE and IT and their benefits during interpretation of challenging cases. Additionally, the use of past patient results, additional available tests (e.g. sFLC), and the electronic medical record to aid in the successful interpretations of these cases will be discussed in a case-based approach.

Learning Objectives:

• Illustrate the current IMWG/CAP guidelines for the laboratory detection and initial diagnosis of monoclonal gammopathies in relation to SPEP and follow-up IFE/IT testing decisions
• Examine the complementary use of both IFE and IT for routine and challenging patient cases
• Utilize all available tools for the accurate interpretation of SPEP and IFE/IT test results