The Value of Serum Immunoglobulin Free Light Chain Assessment in Patients with Monoclonal Gammopathies and Acute Renal Failure

Abstract

OBJECTIVE: Immunoglobulin free light chain (FLC) abnormalities are frequent in patients with monoclonal gammopathies and kidneys are the most affected organs in these patients. Immunoassays which provide quantitative measurement of FLC in serum, indicate monoclonal FLC production by the presence of an abnormal κ to λ FLC ratio. The aim of this study was to assess the serum FLC measurement as a diagnostic tool for detecting plasma cell dyscrasias to compared with standart assays and ascertain its sensitivity and specificity in patients with acute renal failure (ARF). METHODS: Sera from 82 patients with ARF were assessed by serum protein electrophoresis (SPE), serum immunofixation electrophoresis (SIFE) and FLC measurements. The sensitivity and specificity of the FLC ratio for identifying patients with multiple myeloma (MM ) and ARF was compared with SPE and SIFE results. RESULTS: Of 82 patients who were presented with ARF, seven diagnosed multiple myeloma by using serum protein electrophoresis, immunofixation electrophoresis, and bone marrow biopsy tecniques. Of cases 8 patients had not have κ/λ ratio within the published reference range (0.26-1.65); κ/λ ratio based on FLC measurements had 96 % specificity, 71% sensitivity and 62.9 % positive predictive and 97.3% negative predictive value for myeloma diagnoses. CONCLUSION: Patients with MM who were presented with acute renal failure had low sensitivity and specificity for к/λ FLC ratio compared to SPE and SIFE. As a consequence of making a more accurate comment about this method, prospective, well-designed and more patient population studies are needed.

Keywords

• multiple myeloma
• acute renal failure
• immunoglobulin free light chain