Immunoassay Accurately Measures Serum Hepcidin-25

An enzyme linked immunoassay assay (ELISA) can precisely measure the concentration of hepcidin-25 in serum.

Hepcidin is a key regulator of iron metabolism deficiency has been linked to hemochromatosis and iron overload, while increased concentrations are found in anemia of malignancy and chronic diseases.

Hepcidin-23 is the active form of the protein that binds to the iron transporter ferroportin to cause its degradation. A sandwich ELISA test using two antihepcidin-25 monoclonal antibodies was compared with the liquid chromatography-mass spectrometry (LC-MS) method. One hundred serum samples from healthy volunteers (ages 18–64 years, mean age 37 years) with a broad ethnic range and an equal number of male and females, and 34 serum samples from cancer patients were tested at the Lilly Research Laboratories, (Eli Lilly and Company; Indianapolis, IN, USA).

The sandwich ELISA was highly specific for hepcidin-25, having a limit of quantification of 10 pg/mL. Serum concentrations of hepcidin-25 measured by ELISA correlated with hepcidin-25 concentrations measured by using an independent LC-MS assay. Hepcidin-25 concentrations were increased in 34 patients with cancer (median 54.8 µg/L, 25% - 75% range 23.2 - 93.5 µg/L,) and 76 with rheumatoid arthritis (median 10.6 µg/L, 25% - 75% range 5.9 - 18.4 µg/L,) compared with 100 healthy individuals (median 1.20 µg/L, 25% - 75% range 0.42 - 3.07 µg/L.

This sandwich ELISA could also be used to help diagnose iron deficiency anemia in difficult cases in which it may coexist with anemia of chronic disease. In uncomplicated iron deficiency, hepcidin concentrations would be expected to be quite low, whereas in anemia of chronic disease without coexisting iron deficiency, hepcidin concentrations would be expected to be increased. In patients with anemia of chronic disease, a relatively low serum hepcidin concentration might also indicate the presence of coexisting iron deficiency. The study was published in September 2010 in Clinical Chemistry.

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