The transferrin saturation index corresponds to the amount, in percentage, of iron that is bound to transferrin. This way, it is possible to assess whether there is an excess or lack of iron and whether it is being transported through the body correctly.
Transferrin is a protein produced mainly by the liver that is responsible for transporting iron in the blood and changes in its levels can directly affect the measurement of the transferrin saturation index. Understand better what transferrin is and what its dosage is for.
In case of changes in the transferrin saturation index, it is recommended to consult a hematologist or general practitioner. Its interpretation is normally made taking into account the results of other blood tests, such as ferritin measurement.
What is it for
The transferrin saturation index is indicated for:
- Identify iron deficiency;
- Check whether there is excess iron in the body;
- Assess iron transport in the blood.
Analysis of the transferrin saturation index is indicated mainly in cases of suspected iron deficiency anemia. In addition to its measurement, it is common for the doctor to recommend other blood tests, such as a blood count and ferritin measurement, for a more detailed evaluation. Find out about other tests recommended to confirm anemia.
Read too: Iron deficiency anemia: what it is, symptoms, causes and treatment
Reference values
Generally, the normal transferrin saturation index value ranges from 20 to 50% in men and 15 to 50% in women. However, your reference values may be different depending on the laboratory where the test was carried out.
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What does the result mean
The result of the transferrin saturation index must be analyzed by the doctor, who normally also takes into account other blood tests, such as the measurement of ferritin, transferrin and/or serum iron, for its interpretation.
Low transferrin saturation index
The main causes of low transferrin saturation include:
- Iron deficiency;
- Use of contraceptives with estrogen;
- Pregnancy;
- Malnutrition;
- Cancer.
The transferrin saturation index is low, especially when the body’s iron supply drops, which is common in cases of iron deficiency anemia, for example. See what iron deficiency anemia is and the symptoms.
High transferrin saturation index
The main causes of high transferrin saturation index are:
- Excessive use of iron supplements;
- Kidney diseases, such as nephrotic syndrome, which can lead to loss of transferrin in the urine;
- Alcoholic hepatitis or cirrhosis, which can reduce transferrin production;
- Frequent blood transfusions;
- Hemochromatosis, due to excessive absorption of iron from the intestine.
However, a high transferrin saturation index normally indicates an excess of iron in the body, which can affect organs such as the heart and/or liver and cause symptoms such as tiredness, joint pain and yellowing of the skin and eyes. Find out more symptoms of excess iron in the blood.
Bibliography
- THE UNIVERSITY OF IOWA – LABORATORY SERVICES HANDBOOK. Iron Panel (IRON, TRANSFERRIN, TIBC and % SATURATION). 2019. Available at: <https://www.healthcare.uiowa.edu/path_handbook/handbook/test1151.html>. Accessed on January 5, 2024
- STATPEARLS. Iron Binding Capacity. 2023. Available at: <https://www.ncbi.nlm.nih.gov/books/NBK559119/>. Accessed on January 5, 2024
- STATPEARLS. Hemochromatosis. 2023. Available at: <https://www.ncbi.nlm.nih.gov/books/NBK430862/>. Accessed on January 5, 2024
- WANTED, Salina et al. Alcoholic Hepatitis Mimicking Iron Overload Disorders With Hyperferritinemia and Severely Elevated Transferrin Saturation: A Case Report. Cureus. Vol.15, n.7. e41727, 2023
- ELSAYED, M.E; SHARIF, M.U; STACK, A.G . Chapter Four – Transferrin Saturation: A Body Iron Biomarker. In: Advances in Clinical Chemistry. ELSEVIER, 2016. 71-97.
