Total Iron Binding Capacity
Understanding Total Iron Binding Capacity
What is Total Iron Binding Capacity?
The Total Iron Binding Capacity test helps to assess the ability of blood to attach to iron and transport it to various parts of the body. It shows the total binding capacity of transferrin, the protein in the blood that is essential to bind iron and facilitate its movement in the body. Doctors use this test to help determine iron deficiency or iron overload.
Iron is an important nutrient required to perform numerous bodily functions. Iron helps produce healthy red blood cells (RBCs). It is a crucial part of hemoglobin, the protein in RBCs that combines with oxygen and is transported to various body parts. Besides these, iron provides energy, improves concentration, promotes healthier nails, skin, and hair, strengthens the immune system, etc. Usually, the body cannot produce iron by itself and thus it is absorbed from the foods we eat or from supplements.
Iron is transported throughout the body by transferrin, largely produced by the liver. Transferrin is a protein that attaches iron molecules and transports iron in the blood plasma. In a healthy person, most iron is incorporated into the hemoglobin within developing RBCs in the bone marrow. The remaining amount is stored in the tissues as ferritin or hemosiderin. The Total Iron Binding Capacity test is typically used along with iron and ferritin tests to evaluate if you are suspected of having too much or too little iron stored in your body. Signs and symptoms associated with low iron levels may include pale skin, fatigue, headaches, weakness, brittle nails, etc, while those associated with excess iron may include joint pain, abdominal pain, low sex drive, damage to the heart or liver, etc.
Usually, overnight fasting is preferred but not mandatory before undergoing the Total Iron Binding Capacity test. However, it is also important to inform the doctor about any of the medicines you are taking, especially iron supplements, as some of them may affect your iron levels and need to be adjusted or temporarily discontinued before the test.
Test result ranges are approximate and may differ slightly between labs depending on the methodology and laboratory guidelines. Discuss your symptoms and specific test results with your doctor to help them correlate your clinical and laboratory findings. The test results will help the doctor determine your medical condition, recommend lifestyle modifications such as diet and exercise, decide whether or not medications are required to manage your condition and formulate your overall treatment plan.
Note: Though TIBC is a reflection of the amount of transferrin available, TIBC and transferrin are not synonymous.
What is Total Iron Binding Capacity used for?
The Total Iron Binding Capacity test can be done:
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As part of iron studies.
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To determine the capacity of the blood to transport iron.
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In case of abnormal results hemoglobin and hematocrit on complete blood count.
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In case of signs and symptoms of iron deficiency such as chronic fatigue/tiredness, dizziness, weakness, headaches, pale skin (pallor), etc.
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In case of signs and symptoms of iron overload such as joint pain, fatigue, weakness, weight loss, lack of energy, abdominal pain, loss of sex drive, organ damage, such as in the heart and/or liver, etc.
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To monitor ongoing treatment for iron deficiency anemia or iron overload.
What does Total Iron Binding Capacity measure?
The Total Iron Binding Capacity test measures the ability of your blood to bind and transport iron, and therefore reflects your body's iron stores. TIBC correlates with the amount of transferrin, a protein, in your blood, that helps bind iron and facilitates its transportation in the blood. Usually, about one-third of the transferrin measured is being used to transport iron, and this is called transferrin saturation.
Interpreting Total Iron Binding Capacity results
Interpretations
Normal Range: 250 to 425µg/dL
TIBC Test results are usually interpreted in combination with other iron tests as follows:
Iron |
TIBC |
UIBC |
Transferrin Saturation |
Ferritin |
Condition |
Low |
High |
High |
Low |
Low |
Iron Deficiency |
High |
Low |
Low |
High |
High |
Hemochromatosis, Hemosiderosis |
Low |
Low/Normal |
Low/Normal |
Low/Normal |
High/Normal |
Chronic Illness |
High |
Normal/Low |
Low/Normal |
High |
High |
Hemolytic Anemia |
Normal/High |
Normal/Low |
Low/Normal |
High |
High |
Sideroblastic Anemia |
High |
Normal |
Low |
High |
Normal |
Iron Poisoning |