We considered both HLC and IFX as qualitative variables regarding to the type of monoclonal component unveiled (IgM , IgMk or negative if no monoclonal component detected). gl Five patients (1 with IgM and 4 with IgMk) were treated and followed by HLC assay. Median IgM spike was 3.1 g/L. Median CA titre is 1/256 in patients with normal HLC result and 1/2048 in patients with abnormal HLC results (p-value = 0.0306 Wilcoxon test). Keywords: cold agglutinin disease; heavy chain/light chain antibodies; Hevylite; protein electrophoresis; serum immunofixation EN cold agglutinin disease heavy chain/light chain antibodies Hevylite protein electrophoresis serum immunofixation e67 e70 4 08/10/22 20220815 NES 220815 Cold agglutinin disease (CAD) is a rare disorder affecting 15% of patients with autoimmune hemolytic anaemia.1 Most cases of primary CAD produce a monoclonal cold agglutinin IgM, suggesting a clonal proliferation of cells from a lymphoproliferative disorder: monoclonal gammopathy of undetermined significance (MGUS), lymphoplasmacytic disorder or marginal zone lymphoma.2,3 Management of patients with CAD often requires characterization and quantification of the monoclonal component,4 but existing methods leave unmet needs. [Extracted from the article]