Unsaturated iron-binding capacity (UIBC)

UIBC measures the portion of the iron-binding capacity of blood proteins, mainly transferrin, that is not occupied by iron. It is used together with serum iron and total iron-binding capacity when investigating iron deficiency or excess. It helps assess how fully transport proteins are occupied and does not replace ferritin assessment.

High or low UIBC may depend on transferrin concentration and inflammation. Conclusions are based on the combination of markers, rather than on free binding capacity alone. The doctor assesses the result together with symptoms, medical history and other investigations. The reference values of the individual laboratory are used for comparison, and changes over time are considered during follow-up.

• Assess the unoccupied portion of iron-binding capacity.
• Complement investigation of the causes of anaemia.