Total Iron Binding Capacity (TIBC)

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Latest Edit: Hector 2014-03-21 (EDT)

See Also Lab Tests

This test is used to assess iron metabolism in patients who are suspected of having iron deficiency, overload, or poisoning. [1], [2]


  • Roughly 70% of the iron in the body is found in the hemoglobin of the red blood cells (RBCs), while the remaining 30% is stored in the form of ferritin and hemosiderin.
  • Iron is supplied by the diet. About 10% of the ingested iron is absorbed in the small intestine and transported to the plasma, where the iron is then bound to a protein called transferrin and carried to the bone marrow to be incorporated into hemoglobin.
  • TIBC is therefore a measurement of all proteins available for binding mobile iron. It is also an indirect yet accurate measurement of transferrin.

Patient Preparation

  • Fasting is required for 12 hours before the blood test. Water is permitted.
  • Factors which can cause increased levels
  • Recent blood transfusions, ingestion of a meal high in iron content, hemolytic diseases
  • Durgs: Fluorides and oral contraceptives
  • Factors which can cause decreased levels
  • Drugs: ACTH and chloramphenicol

Clinical Implications

High levels indicate:

  • Estrogen therapy
  • Pregnancy (late)
  • Polycythemia vera
  • Iron-deficiency anemia

Low levels indicate:

  • Malnutrition
  • Hypoproteinemia
  • Inflammatory diseases
  • Cirrhosis
  • Hemolytic anemia
  • Pernicious anemia
  • Sickle cell anemia

Associated Tests

  • Ferritin


  1. Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.
  2. Weatherby Dicken, Ferguson Scott (2002) Blood Chemistry and CBC Analysis: Clinical Laboratory Testing from a Functional Perspective, Bear Mountain.