SAGE IVD recommended listing the immunofixation electrophoresis test category in EDL 5:
• as a disease-specific IVD for use in health care facilities with clinical laboratories (Section II.b Cancer);
• using capillary electrophoresis as assay format;
• using serum as specimen type;
• to aid in the diagnosis, monitoring and prognosis of monoclonal gammopathies. SAGE IVD also recommended including a note to the EDL stating that this test is recommended for use in specialized health care settings/clinical laboratories.

The application proposed the inclusion of an immunofixation electrophoresis test using capillary electrophoresis as assay format in the EDL 5. It was pointed out that protein electrophoresis and immunofixation are two linked tests. If laboratory professionals have the technical skill level and the equipment to do one of these, they can do the other because they are closely paired. Serum is the main specimen type for immunofixation electrophoresis using a capillary method. There was some discussion about the applicability of capillary methods to urine samples. Concern was expressed on high costs of immunofixation tests, particularly for LMICs, and that listing in the EDL may lead to price increases. Centralized diagnostics could allow cost-effective implementation, as could the use of multipurpose equipment to optimize resources. Additionally, it was suggested that SAGE IVD could issue a separate statement calling for equitable pricing mechanisms and guidance for implementation.

No systematic reviews on diagnostic accuracy of protein tests (PEP, IFE, FLC) were provided by the applicant. Primary studies on (comparative) diagnostic accuracy in clinically relevant settings (in which suspected patients are included) are lacking. Only one reference (#28) provided relevant evidence, but the sample is small and the reference standard may be at high risk of introducing bias. There were no systematic reviews on clinical utility. Although the current evidence does not support clinical utility, the iStopMM study (reference #36) implies that trial results are underway, which would allow for an excellent comparison of the value of PEP (gel+ capillary) + FLC on clinical outcomes. Currently there are no cost-effectiveness studies available, and thus insufficient evidence for cost-effectiveness of protein tests. Current evidence on diagnostic accuracy is lacking for protein tests. More studies on comparative diagnostic accuracy of these tests compared to contemporary alternative tests are warranted to make an informed evidence based decision. Downstream consequences on clinical utility and cost-effectiveness are unknown, and depend greatly on clinical consequences, and availability and effectiveness of treatment.

The selection and use of essential in vitro diagnostics: report of the fifth meeting of the WHO Strategic Advisory Group of Experts on In Vitro Diagnostics, 2024. World Health Organization. (To be published)