Total Iron Binding Capacity, or TIBC, measures the total capacity of your blood to bind and transport iron, and therefore reflects your body’s iron stores. TIBC correlates with the amount of the protein transferrin in your blood, available to bind iron. Transferrin is a protein that attaches iron molecules and transports iron in the blood plasma. Transferrin is largely made in the liver and regulates your body’s iron absorption into the blood. While the two tests (TIBC and transferrin) are different, they measure essentially the same thing and most laboratories only measure one or the other. A few laboratories are now measuring the number of sites on transferrin that are not already carrying iron; this is referred to as unsaturated iron binding capacity (UIBC). This number can be added to the serum iron to calculate the TIBC.See MoreSee Less
