Total iron-binding capacity (TIBC) reflects how much iron your blood could carry if transferrin, the main iron transport protein, were fully loaded. The typical reference range is about 250–370 μg/dL. High TIBC usually suggests iron deficiency, because the body increases transferrin production when iron stores are low. Low TIBC can be seen with inflammation, liver disease, malnutrition, or iron overload. On its own, TIBC is incomplete; it is most useful when interpreted alongside ferritin, serum iron, and transferrin saturation.