The total iron binding capacity test is a blood test that measures your blood’s ability (capacity) to attach (bind) to iron and carry it throughout your body. Healthcare providers use it to help diagnose iron-deficiency anemia and other iron metabolism conditions.
More specifically, a TIBC test shows the amount of transferrin in your blood. Transferrin is a protein your liver makes that regulates the absorption of iron into your blood.
Your body needs iron to make healthy red blood cells. Red blood cells carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organ function.