Total iron binding capacityDefinition:
Total iron binding capacity (TIBC) is a blood test to see if you have too much or too little iron in the blood. Iron moves through the blood attached to a protein called transferrin. This test helps your doctor know how well that protein can carry iron in the blood.
How the Test is Performed:
A blood sample is needed.
How to Prepare for the Test:
You should not eat or drink for 8 hours before the test.
Certain medicines may affect the result of this test. Your doctor will tell you if you need to stop taking any medicines. Do not stop any medicine before talking to your doctor.
Medicines that can affect the test result include:
- Adrenocorticotropic hormone (ACTH)
- Birth control pills
How the Test will Feel:
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
Why the Test is Performed:
Your doctor may order this test if you have signs or symptoms of low iron (deficiency) due to anemia .
- Iron: 60-170 micrograms per deciliter (mcg/dL)
- TIBC: 240-450 mcg/dL
- Transferrin saturation: 20-50%
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean:
TIBC is usually higher than normal when the body's iron stores are low. This can occur with:
Lower-than-normal TIBC may mean:
- Anemia due to red blood cells being destroyed too quickly (hemolytic anemia )
- Lower-than-normal level of protein in the blood (hypoproteinemia)
- Liver disease, such as cirrhosis
- Decrease in red blood cells from the intestines not properly absorbing vitamin B12 (pernicious anemia )
Sickle cell anemia
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling light-headed
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Brittenham GM. Disorders of iron homeostasis: iron deficiency and overload. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al., eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, Pa: Elsevier Saunders; 2012:chap 34.