(in Gertz et al).Right: High-resolution agarose gel electrophoresis (AgEP) of control serum (C) and of serum (S) and urine (U) from a patient with Waldenström’s macroglobulinemia (anode above). An important monoclonal component is present in the serum, in the gamma region (arrow).Left: By immunofixation using anti-IgG (G), anti-IgA (A), anti-IgM (M), anti-κ(κ) and anti-λ(λ) antisera the serum monoclonal band is typed as IgMk, while no monoclonal protein is detectable by immunofixation in the urine.Inset: The monoclonal IgMk is quantified by densitometry as being 40 g/L.