Total iron binding capacity (TIBC) is a blood test to see if you may 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. For information on how this is done, see: Venipuncture
How to prepare for the test
You should not eat or drink for 8 hours before the test.
Make sure your doctor knows about all the medications you are taking. Some medicines can interfere with test results.
Drugs that can raise TIBC include fluorides and birth control pills.
Drugs that can lower TIBC include ACTH and chloramphenicol.
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 sensation. Afterward, there may be some throbbing.
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 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.
Note: mcg/dl = micrograms per deciliter
What abnormal results mean
TIBC is usually higher-than-normal when the body's iron stores are low. Higher-than-normal TIBC may mean:
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:
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
Yee DL, Bollard CM, Geaghan SM. Appendix: Normal Blood Values: Selected Reference Values for Neonatal, Pediatric, And Adult Populations. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 164.
Marks PW, Glader B. Approach To Anemia In The Adult And Child. . In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 34.
Todd Gersten, MD, Hematology/Oncology, Palm Beach Cancer Institute, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.