The ferritin blood test is requested to see how much iron your body has stored for future use. It is the most useful indicator of iron deficiency, as the ferritin stores can be significantly decreased before any fall in serum iron occurs.
Ferritin is most often requested when a doctor thinks a patient has too little iron in their system. Low iron levels can lead to anaemia and the production of red blood cells that are small (microcytic) and pale (hypochromic). If these typical changes are seen on a “full blood count” then ferritin can be measured to confirm a diagnosis of iron deficiency anaemia.
The test may also be requested when your doctor suspects you have too much iron stored in your body. Iron overload occurs in hereditary haemochromatosis (a genetic disorder which causes too much iron to be absorbed from the diet) but can also occur as a result of repeat blood transfusions and in alcoholics with liver disease.
Ferritin levels are low in long-term iron deficiency. Ferritin may also be decreased if your body's protein levels are very low, as in some cases of malnutrition.
Ferritin levels are high in states of long-term iron overload, especially in haemochromatosis. However, ferritin levels can be high for a number of other reasons including inflammatory conditions and liver disease. Further investigation is therefore required before a diagnosis of iron overload can be made.
Most ferritin is located within the cells of the body, with only a small amount in the blood. When there is damage to organs that contain ferritin (especially the liver, spleen, and bone marrow), ferritin levels can become raised even though the total amount of iron in the body is normal. . Ferritin is therefore a less useful indicator of iron status when measured in people with liver disease, long-term infections, cancer or autoimmune diseases (which are all associated with organ damage).
This article was last reviewed on 12 January 2017. | This article was last modified on 12 January 2017.
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