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Iron Binding Capacity Testing

written by: R. Elizabeth C. Kitchen•edited by: Emma Lloyd•updated: 7/5/2011

If you are planning on having or preparing for an iron binding capacity test, read on to learn more about this test, what it is done for, and what the results mean.

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    An iron binding capacity test is a type of blood test done to determine if there is too little or too much iron in the blood. Iron is attached to transferrin, a protein, and carried in the blood. This tests determines how well transferrin is carrying the iron in the blood.

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    How is it Done?

    iron binding capacity The blood used for this test is typically taken from a vein, most commonly on the back of the hand or inside the elbow. An antiseptic, most often alcohol, is used to clean the area, a tourniquet is tied a few inches above the needle site, and the needle is carefully placed into the vein. The blood will collect in a tube or airtight vial that is attached to the needle. The tourniquet is removed, then the needle is removed. The needle site is then covered with a small square of sterile gauze or a cotton ball to stop any bleeding.

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    How to Prepare

    Not much preparation is needed. All patients should not drink anything or eat anything for eight hours prior to having the iron binding capacity test done. All patients need to make their doctor aware of all medications they take prior to the test because certain medications may interfere with the results of this test. These include:

    • Drugs that can increase TIBC, such as birth control pills and fluorides.
    • Drugs that can decrease TIBC, such as chloramphenicol and ACTH.
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    What Does it Feel Like?

    This test is generally painless. The patient may experience some discomfort when the needle is inserted into their vein. Other patients may experience a slight stinging sensation or a prick. After the test is done and the needle is removed, the patient may feel some throbbing at the puncture site.

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    Why is it Done?

    A doctor may suggest having this test done when they suspect the patient has iron deficiency anemia. If they think that an iron deficiency is the cause. This test may also be done for other medical conditions.

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    Results

    Normal test results include:

    • Iron: 60 to 170 micrograms per deciliter.
    • Transferrin Saturation: 20 to 50 percent.
    • TIBC: 240 to 450 micrograms per deciliter.

    When the iron stores in the body are low, TIBC is typically higher that it should be. When they are higher, it could indicate:

    • Pregnancy (late)
    • Iron deficiency anemia

    When TIBC is lower than it should be, it could indicate:

    • Cirrhosis
    • Hypoproteinemia
    • Liver disease
    • Pernicious anemia
    • Hemolytic anemia
    • Inflammation
    • Malnutrition
    • Sickle cell anemia
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    Possible Risks

    There is very little risk associated with this blood test. These risks may include:

    • Feeling lightheaded or fainting
    • Infection
    • Excessive bleeding
    • Hematoma
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    Serum Iron Test

    This blood test is often done alongside an iron binding capacity. It is done to measure blood-iron levels. This test feels the same as a TIBC, the same risks, and is performed the same way.

    The doctor should be aware of all medications the patient is taking because some can alter test results. These include:

    • Estrogens
    • Methyldopa
    • Birth control pills
    • Cholestyramine
    • Deferoxamine
    • Allopurinol
    • Colchicine
    • Methicillin
    • Testosterone

    When tests results are abnormal, it may indicate:

    • Hemochromatosis
    • Hemolytic anemia
    • Liver tissue death
    • Vitamin B12 or B6 deficiency
    • Several blood transfusions
    • Hemolysis
    • Hemosiderosis
    • Hepatitis
    • Iron poisoning
    • Chronic gastrointestinal blood loss
    • Poor absorption of iron
    • Pregnancy
    • Chronic heavy menstrual bleeding
    • Not enough dietary iron
    • Anemia of chronic disease
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    Resources

    Medline Plus. (2010). Total Iron Binding Capacity. Retrieved on July 3, 2010 from Medline Plus: http://www.nlm.nih.gov/medlineplus/ency/article/003489.htm

    Medline Plus. (2010). Serum Iron. Retrieved on July 3, 2010 from Medline Plus: http://www.nlm.nih.gov/medlineplus/ency/article/003488.htm

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    Image Credits

    Phlebotomy Tray: Bubbels - sxc.hu