Unsaturated Iron Binding Capacity (UIBC)

There are different types of iron tests, including a serum iron test, transferrin test, total iron-binding capacity (TIBC) test, and ferritin blood test. Iron in your blood travels attached to a protein called transferrin, and the iron-binding tests give your provider an indirect way to measure how much transferrin you have and how much of it is carrying iron. Unsaturated iron-binding capacity (UIBC) reflects the portion of transferrin that is not yet carrying iron, so it can be combined with serum iron to estimate TIBC and the percentage of transferrin that is saturated with iron. The amount of iron in your blood varies throughout the day and may be higher in the morning.

You may need testing if you have symptoms of iron levels that are too low or too high. Symptoms of low iron include weakness or fatigue, dizziness, shortness of breath, and arrhythmia. Symptoms of high iron include weakness or fatigue, joint pain, abdominal pain, loss of interest in sex or erectile dysfunction, and skin color changes.

Your provider will consider your symptoms, age, medical history, and other blood test results to interpret iron tests.

Low iron levels may indicate iron deficiency anemia, another type of anemia, or thalassemia, an inherited blood disorder.

High iron levels may indicate hemochromatosis, lead poisoning, or liver disease.

Looking at iron together with iron-binding measures can help tell apart low iron from true iron deficiency versus low iron from inflammation or other long-term illness. Transferrin saturation tends to be low in iron deficiency and high when the body is overloaded with iron.

Most conditions causing too little or too much iron can be treated with supplements, dietary changes, medicines, and other therapies.

Not all abnormal results indicate a medical condition needing treatment. Some medicines, including birth control pills and estrogen treatments, can affect iron levels.