TIBC and transferrin

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Also known as: Total iron-binding capacity; total iron saturation; transferrin saturation
Related tests: Iron, ferritin, iron studies

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

Sample Required?

A blood sample drawn 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?

Transferrin is the main protein in the blood that binds iron and transports it around the body. These tests either indirectly or directly measure the amount of transferrin in the blood available to transport iron. It is difficult to interpret iron levels in the blood without knowing how much of the binding protein transferrin is also present. TIBC (total iron binding capacity), UIBC and transferrin are three different tests that measure the same thing – the amount of iron that can be transported in your blood.

The amount of iron that can be transported in the blood depends on the blood level of the protein transferrin. Transferrin attaches (binds) onto iron and carries it around the body in the bloodstream.

The TIBC test works by first measuring how much iron is in the blood sample, then seeing how much extra iron it is possible for that blood sample to attach to – which will depend on how much transferrin is in the blood. The UIBC is different way of measuring the same thing. The transferrin test is a newer test in which the actual amount of transferrin protein in the blood is measured directly.

Your local laboratory may perform one or more of these tests, depending on the facilities available there.

How is the sample collected for testing?

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

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

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