Serum and liver isoferritin differences: Evidence that serum ferritin may be underestimated in hyperferritinemia

The authors have used gel filtration chromatography to compare relative antibody affinities of liver ferritin and serum ferritin from patients with idiopathic hemochromatosis and other causes of hyperferritinemia such as liver disease, transfusional iron overload, and cancer. When equal amounts of either liver or serum ferritin were mixed with ¹²⁵I-labeled antiferritin antibody then eluted through an agarose column, they obtained higher antigen-antibody complex recovery with the serum ferritin than liver ferritin. This was more marked in patients with untreated, idiopathic hemochromatosis. Their findings provide additional evidence of different reactivity between serum isoferritins and an antibody prepared against organ-specific ferritin. Further, this suggests that the immunoradiometric assay may underestimate serum ferritin concentration in patients with high ferritin values.