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Total iron-binding capacity of blood serum
Medical expert of the article
Last reviewed: 05.07.2025
Total iron-binding capacity of blood serum is an indicator of transferrin concentration. It should be taken into account that when assessing the transferrin content based on the results of determining the total iron-binding capacity of blood serum, it turns out to be overestimated by 16-20%, since at more than half saturation of transferrin, iron binds to other proteins. The total iron-binding capacity of blood serum is not the absolute amount of transferrin, but the amount of iron that can bind to transferrin. By subtracting the amount of serum iron from the total iron-binding capacity of blood serum, the unsaturated, or latent iron-binding capacity is determined: unsaturated iron-binding capacity = TIBC - serum iron. Normally, the unsaturated iron-binding capacity of blood serum averages 50.2 mmol/L (279 μg/dL).
Reference values (norm) of total iron-binding capacity of blood serum
Age |
Reference values of TIBC |
|
Mcg/dl |
µmol/l |
|
Children under 2 years old | 100-400 |
17.90-71.60 |
Children over 2 years old and adults |
250-425 |
44.75-76.1 |
Based on the determination of iron in the blood serum and the total iron-binding capacity of the blood serum, the saturation coefficient is calculated (the ratio of serum iron to the total iron-binding capacity of the blood serum, expressed as a percentage). Normally, this coefficient fluctuates from 16 to 54, averaging 31.2.
Calculation formula: saturation coefficient = (serum iron/TIBC)×100.