Transferrin: what it is, what it is for and why it is high or low

Transferrin is a protein mainly produced by the liver and its main function is to transport iron to the marrow, spleen, liver and muscles, maintaining the proper functioning of the body.

Transferrin assessment is normally indicated to confirm and differentiate anemia, with its dosage normally indicated together with the iron and ferritin dosage.

Assessment of transferrin concentration in the blood must be done after fasting for 8 to 12 hours, depending on the doctor’s and laboratory’s instructions.

What is it for

The transferrin dosage is normally requested by the doctor to make the differential diagnosis of microcytic anemias, which are those characterized by the presence of red blood cells that are smaller than normal. Therefore, in addition to transferrin, the doctor requests serum iron and ferritin measurement. Learn more about ferritin.

In addition to these tests, hemoglobin electrophoresis may be requested to identify the patient’s hemoglobin type and thus confirm the diagnosis of thalassemia, for example. Learn more about hemoglobin electrophoresis.

It is important that the results of the tests are interpreted by the doctor, as in addition to the concentration of iron, transferrin and ferritin, it is necessary to analyze other tests so that it is possible to check the patient’s general clinical condition.

What is Transferrin Saturation Index

The Transferrin Saturation Index corresponds to the percentage of transferrin that is occupied by iron. Under normal conditions, 20 to 50% of transferrin binding sites are occupied with iron. Understand better what the Transferrin Saturation Index is and the result.

Reference values

Normal blood transferrin values ​​are:

• Men: 215 – 365 mg/dL;
• Women: 250 – 380 mg/dL.

Reference values ​​may vary depending on the laboratory, and it is important to evaluate the result according to the values ​​presented in the exam report.

High transferrin is normally noticed in anemia due to a lack of iron, known as iron deficiency anemia, in pregnancy and in treatment with hormone replacement, mainly estrogen.

What does low transferrin mean?

The main situations in which transferrin is low are:

• Thalassemia;
• Anemia sideroblastic;
• Inflammations;
• Situations in which there is a loss of proteins, such as chronic infections and burns, for example;
• Liver and kidney diseases;
• Neoplasms;
• Nephrosis;
• Malnutrition.

Furthermore, the concentration of transferrin in the blood may also be reduced in anemia of chronic disease, which is a type of anemia that normally occurs in hospitalized people who have chronic infectious diseases, inflammation or neoplasms.