What is a Total Iron Binding Capacity Test?

    Total iron binding capacity (TIBC) is a blood test that measures iron levels in the blood. The test helps measure the ability of a protein called transferrin to carry iron in the blood.

    How much iron is binding to this protein is a proxy for how much iron is in your blood at a given time. Too little or too much iron can indicate a number of medical conditions.

    How Is the Test Performed?

    The TIBC test consists of a simple blood test, where blood is drawn from a vein on the inside of the elbow. A nurse or phlebotomist (medical professional trained to draw blood) swipes the area with alcohol, and ties a rubber band strip around the upper arm to help the veins swell with blood. A needle is then inserted to draw the blood into an airtight vial. Pressure and a bandage are applied at the site where the blood was drawn to stop the bleeding.

    The blood sample will be sent to a lab, where it will be examined.

    How to Prepare for the Total Iron Binding Test

    You will likely need to fast (nothing to eat or drink other than water) for eight hours prior to the test. Tell your doctor about all medications you currently take since some may interfere with the test including:

    • birth control pills
    • fluorides
    • chloramphenicol (an antibiotic)

    Risks of Taking the Test

    There is very little risk to having blood drawn.

    In rare cases, complications might include:

    • difficulty drawing blood from some people
    • excessive bleeding
    • fainting or feeling light-headed
    • hematoma (bruise from blood under the skin)
    • infection

    Why Is the Total Iron Binding Capacity Test Performed?

    A TIBC test is usually performed if the doctor suspects you may have low iron, otherwise called iron deficiency or anemia.