RED CELLS Immunoassay for human serum hepcidin

We developed and validated the first serum enzyme-linked immunosorbent assay for hepcidin, the principal iron-regulatory hormone that has been very difficult to measure. In healthy volunteers, the 5% to 95% range of hepcidin concentrations was 29 to 254 ng/mL in men (n 65) and 17 to 286 ng/mL in women (n 49), with median concentrations 112 versus 65 (P < .001). The lower limit of detection was 5 ng/mL. Serum hepcidin concentrations in 24 healthy subjects correlated well with their urinary hepcidin (r 0.82). Serum hepcidin appropriately correlated with serum ferritin (r 0.63), reflecting the regulation of both proteins by iron stores. Healthy volunteers showed a diurnal increase of serum hepcidin at noon and 8 pm compared with 8 am, and a transient rise of serum hepcidin in response to iron ingestion. Expected alterations in hepcidin levels were observed in a variety of clinical conditions associated with iron disturbances. Serum hepcidin concentrations were undetectable or low in patients with iron deficiency anemia (ferritin < 10 ng/mL), iron-depleted HFE hemochromatosis, and juvenile hemochromatosis. Serum hepcidin concentrations were high in patients with inflammation (C-reactive protein > 10 mg/ dL), multiple myeloma, or chronic kidney disease. The new serum hepcidin enzymelinked immunosorbent assay yields accurate and reproducible measurements that appropriately reflect physiologic, pathologic, and genetic influences, and is informative about the etiology of iron disorders. (Blood. 2008;112:4292-4297)