Ferritin test

Most of the iron stored in your body is attached to a protein called ferritin. Ferritin is found mostly in your liver, but also in you bone marrow, spleen and muscles. The amount of ferritin in your blood helps your healthcare provider understand how much iron your body is storing.

Ferritin is mainly found inside the cells in your body, with only a small amount in your blood. When there's damage to organs that contain ferritin, and when inflammation is present, ferritin levels in your blood can be raised even though the total amount of iron in your body is normal. Measuring ferritin levels may not be particularly helpful if you have liver disease, long-term infections, cancer or autoimmune diseases. If this is happening for you, your healthcare provider will use other iron tests as well.

Measuring iron in your blood isn't reliable on it's own, so ferritin is measured instead. A ferritin test is ordered when your healthcare provider suspects you have low iron stores (iron deficiency). If your iron stores are very low, you may not be able to make enough red blood cells, and can get an iron deficiency anaemia. Less commonly, you may have too much iron (iron overload or haemochromatosis which runs in families). 

A ferritin test can also be done to check if treatment to raise or lower your iron levels is working. The ferritin test is often ordered along with other blood tests, eg, a full blood count (FBC).

If you follow a strict vegan diet, or have another risk for iron deficiency, you healthcare provider may recall you for a ferritin test once a year, along with a vitamin B12 test. 

Generally, you won't need to do anything before having this test. It can be done at any time of the day. It's a simple blood test where a small amount of blood is taken by placing a needle in a vein in your arm. Read more about blood tests.

Your healthcare provider will work out what your ferritin test results mean along with other blood test results and symptoms. They will share your results with you in the way you have agreed, and discuss what to do about it.

Low ferritin levels

Low ferritin levels often mean that your iron levels are low (iron deficiency).

High ferritin levels

High ferritin levels can be caused by the following:

• Taking iron supplements.
• A diet that's too high in iron.
• Multiple blood transfusions
• A mild inflammation which will pass. If your healthcare provider suspects this, they may ask you to repeat the test in a few months to see if your ferritin levels are back to normal.
• A medical condition your healthcare provider already knows about, so no change is needed.
• A new problem that needs to be looked into further. This could be:
  • a build up of iron in your body – haemochromatosis
  • alcohol misuse, thalassemia or haemolytic anaemias which destroy red blood cells
  • Hodgkin's disease, leukaemia, infection or inflammatory conditions (eg, arthritis or lupus).