Replacing Acid-Heat Precipitation with Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis Improves Detecting Bence-Jones proteinuria

Background: Detecting Bence-Jones protein in urine is essential for determining plasma cell dyscrasia and multiple myeloma. Conventionally, acid-heat precipitation assay is used for detecting Bence-jones protein in most medical laboratories; however, because of the low accuracy of this test, other more sensitive tests like urine electrophoresis are recommended. Materials and Methods: In this study, the presence of Bence-jones protein in the urine of patients suspected to monoclonal gammopathies were compared using acid-heat precipitation, capillary immunoelectrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Moreover, the subsets of light chain (κ & λ) in capillary immunoelectrophoresis were determined. Results: Our data showed high false negative results (77.7%) using acid-heat precipitation assay in comparison with polyacrylamide gel and capillary immunoelectrophoresis (0%). Conclusion: Collectively, in spite of advantages like easy performance and low cost, acid-heat precipitation assay is not reliable for determining Bence-jones proteinuria in medical laboratories due to its low sensitivity. Therefore, it is recommended to be replaced with more sensitive assays like electrophoresis.