What does a low or high ferritin mean?
A low ferritin means low iron stores and is the usual sign of iron deficiency, which can lead to anaemia and tiredness. Your doctor will look for a cause, such as blood loss or poor absorption.
A high ferritin can mean too much iron, but more often reflects inflammation or infection (ferritin rises as part of the body's response), so it is interpreted with other tests rather than alone.
What happens next?
Low ferritin is usually treated by finding and addressing the cause and replacing iron (tablets or, sometimes, an infusion). Persistently high ferritin may prompt tests for conditions such as iron overload (haemochromatosis) or for sources of inflammation.
Common questions
Can ferritin be normal even with iron deficiency?
Yes — because inflammation raises ferritin, it can look 'normal' despite low iron. Doctors may add other iron tests if the picture is unclear.