The UIBC, or “unsaturated iron binding capacity”, is calculated by subtracting the serum iron from the TIBC (Total iron-binding capacity). Taken together with serum iron and percent transferrin saturation clinicians usually perform the TIBC test when they are concerned about anemia, iron deficiency or iron deficiency anemia. Total Iron Binding Capacity equals the Unsaturated Iron Binding Capacity plus serum iron: TIBC = UIBC + Serum Iron. Unsaturated iron binding capacity (UIBC) is an inexpensive alternative to transferrin saturation for detection of hereditary hemochromatosis.