What does iron saturation mean?

Iron saturation or transferrin saturation is measured as a percentage.

It is calculated by dividing the amount of serum iron by total iron binding capacity (TBIC) – serum iron concentration ÷ total iron binding capacity.

A low transferrin saturation percentage may indicate low iron or  iron-deficiency anemia.

A transferrin saturation percentage may indicate iron overload. Transferrin saturation is also called transferrin saturation index (TSI) or transferrin saturation percentage (TS%).Source: CDC Nutritional Report 2019.