Iron and Total Iron-binding Capacity (TIBC)

Also known as: Fe and TIBC, TIBC and Iron, Total Iron-binding Capacity (TIBC), Transferrin Saturation, Unsaturated Iron-binding Capacity (UIBC)

Clinical Use

Order Test

Use

Differential diagnosis of anemia, especially with hypochromia and/or low MCV. The percent saturation sometimes is more helpful than is the iron result for iron deficiency anemia. Evaluate thalassemia and possible sideroblastic anemia; work-up hemochromatosis, in which iron is increased and iron saturation is high. Decrease in iron level after performance of Schilling supports the diagnosis of vitamin B12 deficiency, vide infra. Evaluate iron poisoning (toxicity) and overload in renal dialysis patients, or patients with transfusion dependent anemias. Use of TIBC in iron toxicity may be less useful than previous believed.1 TIBC or transferrin is a useful index of nutritional status.

Special Instructions

Not provided.

Limitations

Ferritin levels are also important for assessing iron deficiency. Low iron levels might not indicate deficiency during acute infections with leukocytosis. Conditions like chronic infections, inflammation, and malignancy can falsely alter iron levels and ferritin readings. TIBC and transferrin levels may be increased due to oral contraceptives, with normal saturation. Hemolysis can interfere with serum iron testing. Parenteral iron or recent blood transfusions before sample collection can yield misleading results.

Test Details