Ferritin

Ferritin is the main way the body stores iron, so the amount in your blood reflects your iron reserves. Iron is needed to make haemoglobin, which carries oxygen in red blood cells.

A low ferritin suggests low iron stores and can be linked with tiredness, but many things cause tiredness. A high ferritin can mean the body holds a lot of iron, but it also rises with inflammation, infection, liver problems and some other conditions, so it is not a simple measure.

Ferritin is best interpreted with other tests, such as haemoglobin and iron studies, and with your symptoms and history. Do not take iron supplements without a test and medical advice, because too much iron can be harmful.