Ferritin

You get iron from eating food or taking supplements. There are iron-only supplements, but many multivitamin/mineral supplements also contain iron.

Too little or too much iron in your body can cause serious health problems if not treated. A ferritin blood test can show how much iron you have stored in your body. It can also help your provider check for types of anemia in which red blood cells are smaller and paler than normal.

Lower than normal ferritin is usually the earliest sign that your body's iron stores are running low. Even before the red blood cells get smaller or anemia shows up, ferritin can drop. Common causes include heavy menstrual bleeding, slow blood loss from the gut, pregnancy, or a diet low in iron.

Higher than normal ferritin can be caused by too much iron in the body (for example, from hereditary hemochromatosis, where levels can climb above 1000 mcg/L), but more often it reflects something else: long-lasting inflammation, infection, liver disease, kidney disease, or certain cancers. Ferritin also rises temporarily with any acute illness, surgery, or injury, because it is an 'acute-phase' protein.

Because ferritin can be raised by inflammation, a 'normal' or even slightly high ferritin does not always rule out iron deficiency in someone who is also unwell. Your provider may look at iron, transferrin, and CRP together to get a clearer picture.

If your ferritin results are not normal, it does not always mean you have a medical condition that needs treatment. Certain medicines can decrease or increase your ferritin levels. If you have questions about your results, talk with your provider.