Ferritin is an iron-protein complex found in most tissues, but particularly the bone marrow and reticuloendothelial system.

Clinically, its importance is:

• as an acute phase protein
• as a non-specific index of liver disease
• its close relationship to body stores of iron. Thus a low serum ferritin implies iron deficiency. Conversely, high ferritin can imply iron overload states. However, given the first two points in the list, ferritin levels must be interpreted in the light of ongoing inflammation and liver disease.