Serum Free Light Chain (FLC) Analysis: A Guiding Light in Monoclonal Gammopathy Management.

Background: Monoclonal free light chains (FLCs) were first reported by Dr. Henry Bence Jones over 150 years ago in the urine of patients with multiple myeloma. Now established as important tumor markers, they aid not only in the diagnosis of monoclonal gammopathies but also in their clinical management by indicating the response to treatment and persistence of residual disease.

Analytical issues of serum free light chain assays and the relative performance of polyclonal and monoclonal based reagents.

Serum free light chain (FLC) assays have been incorporated into routine clinical practice and their use is recommended in international guidelines for the management of monoclonal gammopathies. Given that FLCs are not simple analytes, laboratories should be aware of potential analytical issues when using FLC assays, including antigen excess, lot-to-lot variation and non-linearity. Whilst manufacturers of monoclonal antibody-based assays claim that they overcome such issues, the evidence available to date does not support this.

Quantification of β-region IgA monoclonal proteins - should we include immunochemical Hevylite® measurements? Point.

Accurate measurement of IgA monoclonal proteins presents a significant challenge to laboratory staff. IgA heavy/light chain (Hevylite, HLC) analysis is an alternative methodology for monoclonal protein assessment, giving an independent measure of IgAκ and IgAλ concentrations. Clonality is assessed by calculating the ratio of involved immunoglobulin to background uninvolved immunoglobulin concentrations (e.