The MaxDiscovery™ Ferritin ELISA Kit is an enzyme immunoassay that analyzes the quantity of human ferritin in cells, tissues or serum. Ferritin is a 450 kDa ubiquitous protein consisting of 24 subunits that stores iron and releases it in a controlled fashion. The protein acts as a buffer against iron deficiency and iron overload. One of the most prevalent disorders of man is the dietary deficiency of iron and the resulting anemia. Therefore, the assays of iron, total iron binding capacity and other assessments of iron compounds in the body are clinically significant. The presence of iron itself is a major trigger for the production of ferritin, with some exceptions. Free iron is toxic to cells and thus vertebrates use elaborate protective mechanisms. Under steady state conditions the serum ferritin level correlates with total body iron stores. Thus, serum ferritin is the most convenient laboratory test to estimate iron stores. Like most ELISA assays, the MaxDiscovery™ Ferritin ELISA Kit relies on Horseradish Peroxidase (HRP) and the (3,3´,5,5´-tetramethylbenzidine) TMB substrate. TMB is a chromogen that yields a blue color when oxidized with hydrogen peroxide (catalyzed by HRP) and has major absorbances at 370 nm and 652 nm. The color then changes to yellow with the addition of acid with maximum absorbance at 450 nm. The relative amount of ferritin protein in the cells will be directly proportional to the amount of signal that is obtained at 450 nm.