Transferrin: The Protein That Carries Iron

Transferrin is a protein in your blood that carries iron to different parts of your body. It is made in the liver. When your body does not have enough iron, your liver makes more transferrin to try to collect and transport as much iron as possible. When you have inflammation, liver problems, or poor nutrition, your body may make less transferrin.

Transferrin is one piece of the iron picture. When it is looked at together with other iron markers - like ferritin, serum iron, and saturation index - it helps explain why someone might have low or high iron levels.

High transferrin may mean your body is low in iron because of poor intake, poor absorption, problems using iron, or blood loss. Pregnancy and the oral contraceptive pill can also increase transferrin levels.

Low transferrin can happen when your body is dealing with inflammation, liver disease, kidney disease (where protein is lost), or poor nutrition. Low transferrin can also appear in cases of iron overload, because the body reduces transferrin production when iron stores are high.