These tests measure the amount of iron that can be transported in your blood. Transferrin is a protein that carries iron in your blood. When iron stores are low, transferrin levels increase, and when there is too much iron, transferrin levels decrease. Transferrin is usually requested as part of the group of tests known as iron studies, which includes other tests relating to the body' s iron levels. Total iron binding capacity (TIBC) is an older test that is sometimes still performed by some labs. TIBC and transferrin give the same information — the amount of iron capable of being transported in the blood.
Why get tested?
Iron is an essential mineral that is needed by the body to form haemoglobin. Haemoglobin is the protein in red blood cells that binds oxygen in the lungs and releases it as blood travels to other parts of the body.
If your iron levels are too low your body will not be able to make enough haemoglobin needed to function normally. This condition is known as iron-deficiency anaemia. It is also possible to have too much iron. This is known as iron overload and it may be caused by an inherited condition called haemochromatosis.
Iron is stored in a protein called ferritin in the body’s cells until it is needed. When the iron is required, it is released from ferritin and enters the bloodstream bound to transferrin. Your body makes transferrin according to your need for iron. When iron stores are low, transferrin levels increase, and when there is too much iron, transferrin levels are low. The transferrin test measures the amount of transferrin in the blood
For more on how the body uses iron and what happens if you do not have enough or if you have too much, see Iron Studies.
Having the test
A blood sample, usually taken from a vein in the arm.
Reading your test report
Your results will be presented along with those of your other tests on the same form. You will see separate columns or lines for each of these tests.
It is not possible to accurately interpret transferrin or TIBC results without looking at other tests in the iron studies group.
High transferrin or TIBC
A high transferrin or TIBC may be due to iron deficiency. When the body lacks iron it increases its ability to transport iron by increasing transferrin production.
However, a high transferrin or TIBC does not always indicate iron deficiency. For example, transferrin levels increase during pregnancy. Transferrin levels may also increase as a side effect of some medications.
For these reasons, your doctor will look at all the results in the iron studies profile to see if the overall pattern suggests iron deficiency or another cause.
Low transferrin or TIBC
The most common cause of a low transferrin is acute inflammation. Transferrin production by the body decreases during a period of inflammation (for example after a recent operation, during an infection, or if you have an autoimmune condition).
A low transferrin is also seen in people who have iron excess. Other results in the iron studies profile (such as a high ferritin and high transferrin saturation) may also indicate this diagnosis.
|A summary of the changes in iron tests seen in various disorders.
TIBC or Transferrin
Your results will be compared to reference intervals (sometimes called a normal range).
If your results are flagged as high or low this does not necessarily mean that anything is wrong. Blood test results must be interpreted with an understanding of your own particular symptoms and clinical situation. For this reason, your results are best interpreted by your own doctor.
Questions to ask your doctor
The choice of tests your doctor makes will be based on your medical history and symptoms. It is important that you tell them everything you think might help.
You play a central role in making sure your test results are accurate. Do everything you can to make sure the information you provide is correct and follow instructions closely.
Talk to your doctor about any medications you are taking. Find out if you need to fast or stop any particular foods or supplements. These may affect your results. Ask:
Any more to know?
If you are diagnosed with iron deficiency you may need to take iron supplements, or your doctor may arrange for you to have an intravenous iron infusion. In very severe iron deficiency due to bleeding, you may require a blood transfusion. It is not recommended to take iron supplements unless advised to do so by your doctor.
There are many causes of iron deficiency. If you have iron deficiency, your doctor will discuss the possible causes with you and will arrange any further necessary tests.
Pathology Tests Explained (PTEx) is a not-for profit group managed by a consortium of Australasian medical and scientific organisations.
With up-to-date, evidence-based information about pathology tests it is a leading trusted sources for consumers.
Information is prepared and reviewed by practising pathologists and scientists and is entirely free of any commercial influence.