Serum free light chain assessment in monoclonal gammopathy and kidney disease.

Abnormalities of immunoglobulin free light chains (FLCs) are frequently present in patients with monoclonal gammopathies and can cause kidney disease. The recent introduction of highly sensitive immunoassays that measure FLCs to levels below those present in normal individuals has provided a new tool for diagnosis and management in this setting. Here, we review the biology of FLC production in health and disease, and the utility of FLC immunoassays in the assessment of monoclonal gammopathies in kidney disease.