The Total Iron Binding Capacity (TIBC) test is a blood test that measures the amount of transferrin, a protein that binds to iron in the blood, available to bind with additional iron. The TIBC test is often used in conjunction with other tests to evaluate iron status and diagnose conditions such as iron deficiency anemia. In cases of iron deficiency, the TIBC is typically high because there is a greater amount of transferrin available to bind with iron. Conversely, in cases of iron overload, the TIBC is typically low because transferrin becomes saturated with iron. The TIBC test is a useful tool in assessing iron metabolism and can aid in the diagnosis and management of various iron-related disorders.