Total Iron-Binding Capacity Calculator

About this calculator

Total iron-binding capacity (TIBC) is a lab measure of the blood's total capacity to bind iron to transferrin, the main iron-transport protein, and it is most often calculated directly from a measured serum transferrin level using the relationship TIBC (µg/dL) ≈ transferrin (mg/dL) × 1.42, since transferrin is the near-exclusive iron carrier in circulation. From TIBC and serum iron, two further values follow: UIBC (unsaturated iron-binding capacity, the unused portion of TIBC) and transferrin saturation (serum iron divided by TIBC), the percentage of transferrin actually carrying iron.

Physicians order TIBC and transferrin saturation as part of an iron-deficiency or iron-overload workup, since the pattern of high TIBC with low saturation points toward iron-deficiency anemia, while low TIBC with high saturation is characteristic of iron overload conditions like hemochromatosis or inflammation-driven changes in iron handling. Hematologists and primary care clinicians use these values together with serum ferritin to distinguish between the different causes of anemia.

This calculator takes your serum transferrin (or TIBC directly) and serum iron and returns TIBC, UIBC and transferrin saturation.