The DRG:HYBRiD-XL Hepcidin 25 (bioactive) is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of Hepcidin 25 in serum or plasma (EDTA-, heparin-or citrate plasma).Only for use with the DRG:HYBRiD-XL Analyzer.Hepcidin is an iron homoeostasis regulator peptide. The bioactive peptide Hepcidin 25 is generated predominantly in the liver by proteolytic cleavage of the C-terminal 25 amino acids of prohepcidin (1). Subsequent N-terminal processing of Hepcidin 25 results in smaller peptides of 20-24 amino acids that show greatly reduced activity and accumulate in the urine (2). Although originally identified as antimicrobial peptide (3), Hepcidin 25 is now established as a major regulator of dietary iron absorption and cellular iron release (4). Hepcidin exerts its regulatory function by counteracting the function of ferroportin, the major cellular iron exporter in the membrane of macrophages, hepatocytes, and the basolateral site of enterocytes. Hepcidin 25 induces the internalization and degradation of ferroportin, resulting in increased intracellular iron stores, decreased dietary iron absorption, and decreased circulating iron concentrations (5). Hepatocellular hepcidin synthesis decreases under conditions of increased demand for circulating iron like iron deficiency, hypoxia, anemia, and erythropoiesis. In contrast, hepcidin synthesis is induced by inflammation and infection (6). Serum Hepcidin 25 has been shown to add value to identify and differentiate specific disease conditions. Hepcidin deficiency causes hereditary hemochromatosis, characterized by body iron overload that may progress to liver cirrhosis (7). In addition, low Hepcidin 25 concentration can be induced by iron loading anemias (8) and chronic hepatitis C (9). In contrast, high Hepcidin 25 levels have been found in iron-refractory iron-deficiency anemia (10), during infection, chronic kidney disease (11), and after intensive exercise, explaining the high iron deficiency among athletes (12).The DRG:HYBRiD-XL Hepcidin 25 (bioactive) Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the principle of competitive binding. The antibody coated wells (ACW) of the reagent cartridges are coated with a monoclonal [mouse] antibody directed towards a unique antigenic site of the Hepcidin 25 molecule. Endogenous Hepcidin 25 of a patient sample competes with a Hepcidin 25-Biotin conjugate (Enzyme Conjugate) for binding to the coated antibody. After incubation the unbound conjugate is washed off. Bound Conjugate is detected by Streptavidin-HRP (Enzyme Complex). After incubation the unbound complex is washed off. The amount of bound enzyme complex is inversely proportional to the concentration of Hepcidin 25 in the sample. Having added the substrate solution, the intensity of colour developed is inversely proportional to the concentration of Hepcidin 25 in the patient sample.