Transferrin
Does this test have other names?
Total iron-binding capacity, TIBC, transferrin saturation
What is this test?
This test measures the amount of the iron transport protein transferrin in your blood.
Your liver makes transferrin. When your body's stores of iron run low, your liver makes more transferrin to get more iron into your blood.
Iron plays many important roles in your body, including helping your red blood cells carry oxygen to the cells in your body. Nearly all the iron in your body is normally attached to transferrin.
Normally, your body carefully keeps track of your iron level and tries to keep it from rising too high or falling too low.
This test can give your doctor more information about health issues like anemia that are affecting your body's iron supply.
Why do you need this test?
You may need this test if your doctor suspects that you have a certain type of anemia. In general, anemia means you have a low number of red blood cells. One type of anemia is iron-deficiency anemia. If you have this type, you don't have enough iron to correctly make hemoglobin. Hemoglobin is the substance that helps your red blood cells carry oxygen.
Symptoms of anemia can include:
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Unexplained all over weakness.
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Unexplained fatigue, or lack of energy.
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Pale or yellowish skin color.
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Dizziness.
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Irritability.
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Headaches, especially with activity.
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Shortness of breath or chest pain and fast heartbeat during physical activity.
Less common symptoms include:
Anemia usually happens because of blood loss or because you aren't absorbing enough iron from your food. If you are pregnant, you're also at higher risk of developing this problem.
What other tests might you have along with this test?
Your doctor may also order other tests, including:
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A complete blood count (CBC).
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Tests to measure how much iron is in your blood.
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A test to measure ferritin, a protein that holds most of your body's iron reserves.
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Stool tests.
What do your test results mean?
Test results may vary depending on your age, sex, and health history. Your test results may also vary depending on the lab used. Ask your doctor what your test results mean for you.
Results are given in milligrams per deciliter (mg/dL). The normal range for transferrin is 215 mg/dL to 380 mg/dL. If you have a higher amount, you may have iron-deficiency anemia. If you have a lower level, you may have another problem, such as liver disease or hemolytic anemia.
Transferrin may also be measured using a value called total iron-binding capacity (TIBC). Results are given in micrograms per deciliter (mcg/dL). Normal values are 250 mcg/dL to 450 mcg/dL. A higher level means that you may have iron-deficiency anemia.
Another measurement, called transferrin saturation, checks how many places on your transferrin that can hold iron are actually doing so. Normal values are 15% to 50%. In severe cases of iron-deficiency and anemia, this number may fall below 10%.
Many other health conditions can cause high or low levels of transferrin. The results of these tests, and other tests, can help your doctor determine the cause of your symptoms.
How is this test done?
The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.
Does this test pose any risks?
Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your arm or hand, you may feel a slight sting or pain. Afterward, the site may be sore.
What might affect your test results?
Aspirin, antibiotics, and birth control pills can affect your results.
How do you get ready for this test?
You may need to fast for a period of time, so check with your doctor for specific instructions. Be sure your doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.