Ferritin is a protein synthesised by the liver, and is the main element of the iron reserve. In fact, this protein includes a core of iron (II), which can be used for the formation of haemoglobin, for example. Despite the low serum ferritin concentration, this latter reflects the cellular concentration of ferritin quite accurately.
A high serum ferritin concentration may signify a liver problem (as a result of alcoholism, etc.). Serum ferritin concentration may increase in the case of numerous blood transfusions, but also in the case of chronic infections, chronic inflammation (rheumatoid arthritis, etc.) or kidney disease.
An iron deficiency, which is one of the most common disorders in humans, can also be detected by the assay of ferritin. The serum concentration in ferritin will then be low.