Total iron-binding capacity (TIBC) is a blood test that measures the amount of iron that can potentially be stored in blood.
The test is done to help diagnose known or suspected iron deficiency. It can also provide information about a person's nutritional status. TIBC can help tell the difference between certain types of anemia that require different treatment.
Iron in the blood is vital to life. Iron in red blood cells helps to carry oxygen in the body. The body's iron comes from food. Iron is transported in the blood attached to a molecule called transferrin. The TIBC test measures the maximum amount of iron that can be attached to transferrin.
A healthcare provider usually orders this test when he or she suspects anemia, which is a low red blood cell count. This test may also be used to try to determine the type of anemia present.
In order to measure the TIBC, a blood sample is needed. The blood is usually taken from a vein in the forearm or hand. The blood is then sent to the laboratory for testing.
A person should consult their health professional for specific instructions before taking the test. Generally, no preparation is required.
This test is commonly ordered at the same time as the serum iron level. The values from these two blood tests are examined together. The pattern of these two tests often gives clues to the type of anemia present.
Normal TIBC varies depending on the age and sex of the person. It can also change during pregnancy.
TIBC is increased in iron deficiency anemia, pregnancy, and hepatitis. It can also be increased by the use of oral contraceptives.
TIBC is decreased in starvation, malnutrition, cancer, and hyperthyroidism. Other causes of low TIBC include chronic diseases such as liver disease.
The healthcare provider will discuss the test results with the person and discuss any recommended treatment.
Author:Kimberly Tessmer, RD, LD
Editor:Smith, Mary Ellen, BS
Reviewer:Adam Brochert, MD
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Griffith, W., MD. (1988). Complete Guide to Medical Tests. Fisher Books.