FIGURE 2.

A diagrammatic representation of states of absolute and functional iron deficiencies (AID and FID, respectively) as compared to healthy iron status. FID and AID are characterised by significant reduction or unavailability of iron for erythropoiesis, thereby resulting in clinical anaemia in chronic inflammations, including cancer. FID is a condition of iron deficiency marked by adequate or increased iron stores with elevated hepcidin, while this iron is inaccessible for erythropoiesis. AID, on the other hand, indicates a complete depletion of iron reserves and iron unavailability for red blood cell (RBC) synthesis.