Transferrin Saturation (TSAT)

Transferrin Saturation (TSAT), often called Iron Saturation, calculates the percentage of iron-binding sites on transferrin that are occupied by iron (TSAT % = [Serum Iron / TIBC] x 100, or calculated using transferrin). It reflects how much iron is readily available for delivery to tissues.

• Low TSAT (<15-20%) is a key indicator of functional iron deficiency (insufficient iron delivery for erythropoiesis), even if ferritin is normal/high due to inflammation.
• High TSAT (>45-50%, especially >55-60%) suggests increased iron load and potential risk for iron overload (e.g., hemochromatosis).