Non-transferrin bound iron: A key role in iron overload and iron toxicity

► NTBI and its toxic form LPI appear in plasma when transferrin saturation increases. ► NTBI is avidly taken up by parenchymal cells (especially hepatocytes). ► Labile Iron Pool can be considered as an intracytosolic equivalent of plasma NTBI. ► NTBI can be present in diseases not primarily related to iron overload. ► Therapeutic efforts (phlebotomies, iron chelation) must focus on NTBI elimination.