Blood Iron, Transferrin and Ferritin Tests and Total Iron Binding Capacity (TIBC)

Blood Iron, Transferrin and Ferritin Tests and Total Iron Binding Capacity (TIBC)

General Information

Iron plays several important functions in the body. It is involved in the formation and functioning of hemoglobin found in red blood cells. Most iron is found in hemoglobin, the rest is stored as ferritin. Iron needs a protein, called transferrin, to travel in the blood. Blood iron levels represent the balance between dietary intake and iron losses (menses, loss in stools, etc.). Ferritin levels are useful to assess body iron stores. Iron binding capacity is calculated from blood transferrin levels and is expressed as a percentage. It is used to distinguish the various types of anemia.

The four most frequent iron-related tests are::

• serum iron - measures iron levels in serum; represents iron that is almost completely bound to transferrin;
• transferrin - measures levels of the iron carrier;
• total iron binding capacity (TIBC) - measures the transferrin capacity to bind iron;
• serum ferritin - measures the body's ability to store iron.

What does an abnormal test result mean?

If the result is too high

• Iron
  There may be excessive amounts of iron in the blood, a condition called hemosiderosis or hemochromatosis. Liver problems can also explain elevated results.
• Ferritin
  Ferritin levels may be too high because iron levels are too high. Liver cirrhosis, hyperthyroidism, non iron deficiency anemia and inflammatory states can explain elevated results.
• Transferrin and total iron binding capacity
  This indicates iron deficiency anemia or hemochromatosis.

• Iron
  Indicates iron deficiency anemia. Low iron levels can also be seen in people with poor dietary iron absorption or poor diet. Low iron levels are often associated with certain chronic diseases.
• Ferritin
  Also indicates iron deficiency anemia.
• Transferrin and total iron binding capacity
  In some cases, indicates inflammatory disease or low blood proteins.

Factors that can affect the result of the test

Pregnancy can affect results, usually making them lower. Recent blood transfusion increases the amount of blood iron. Among drugs, oral contraceptives (the "pill") increase blood iron levels and iron binding capacity.

What you need to know before the test

Before going for blood tests, a procedure or other exam, it is best to always bring a list of all the drugs you take (prescription, OTC and natural health products). Unless told otherwise, you should take your medication as usual on the day of the test. When in doubt, ask your pharmacist for more information.