TIBC, UIBC and Transferrin

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Also known as: total iron-binding capacity; total iron saturation; transferrin saturation; unsaturated iron-binding capacity

At a Glance

Why Get Tested?

To learn about your body's iron stores

When to Get Tested?

When your doctor suspects you may have too much or too little iron in your body because of a variety of conditions

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?

You may be instructed to fast for 12 hours before the test; in this case, only water is allowed.

The Test Sample

What is being tested?

Total Iron Binding Capacity, or TIBC, measures the total capacity of your blood to bind and transport iron, and therefore reflects your body's iron stores. TIBC correlates with the amount of the protein transferrin in your blood, available to bind iron. Transferrin is a protein that attaches iron molecules and transports iron in the blood plasma. Transferrin is largely made in the liver and regulates your body’s iron absorption into the blood. While the two tests (TIBC and transferrin) are different, they measure essentially the same thing and most laboratories only measure one or the other. A few laboratories are now measuring the number of sites on transferrin that are not already carrying iron; this is referred to as unsaturated iron binding capacity (UIBC). This number can be added to the serum iron to calculate the TIBC.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in your arm.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

You may be instructed to fast for 12 hours before the test; in this case, only water is allowed.

The Test

Common Questions

Ask a Laboratory Scientist

Article Sources

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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.