Serum and Urine Protein Electrophoresis and Serum-Free Light Chain Assays in the Diagnosis and Monitoring of Monoclonal Gammopathies

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8 Scopus citations


BACKGROUND: Laboratory methods for diagnosis and monitoring of monoclonal gammopathies have evolved to include serum and urine protein electrophoresis, immunofixation electrophoresis, capillary zone electrophoresis, and immunosubtraction, serum-free light chain assay, mass spectrometry, and newly described QUIET. CONTENT: This review presents a critical appraisal of the test methods and reporting practices for the findings generated by the tests for monoclonal gammopathies. Recommendations for desirable practices to optimize test selection and provide value-added reports are presented. The shortcomings of the serum-free light chain assay are highlighted, and new assays for measuring monoclonal serum free light chains are addressed. SUMMARY: The various assays for screening, diagnosis, and monitoring of monoclonal gammopathies should be used in an algorithmic approach to avoid unnecessary testing. Reporting of the test results should be tailored to the clinical context of each individual patient to add value. Caution is urged in the interpretation of results of serum-free light chain assay, kappa/lambda ratio, and myeloma defining conditions. The distortions in serum-free light chain assay and development of oligoclonal bands in patients' status post hematopoietic stem cell transplants is emphasized and the need to note the location of original monoclonal Ig is stressed. The need for developing criteria that consider the differences in the biology of kappa and lambda light chain associated lesions is stressed. A new method of measuring monoclonal serum-free light chains is introduced. Reference is also made to a newly defined entity of light chain predominant intact immunoglobulin monoclonal gammopathy. The utility of urine testing in the diagnosis and monitoring of light chain only lesions is emphasized.

Original languageEnglish (US)
Pages (from-to)1358-1371
Number of pages14
JournalThe journal of applied laboratory medicine
Issue number6
StatePublished - Nov 1 2020


  • Autologous stem cell transplantation
  • Immunofixation electrophoresis
  • Light chain predominant multiple myeloma
  • Monoclonal gammopathy of undetermined significance
  • Multiple myeloma

ASJC Scopus subject areas

  • Medicine(all)


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