Ferritin: a window into iron stores

Iron and ferritin have different roles

Iron is a mineral the body uses to make haemoglobin, the protein that carries oxygen in the blood. Ferritin is a protein that stores iron. The blood test measures ferritin and helps assess iron reserves.

Why the result needs context

Low ferritin may indicate iron deficiency. A high value can reflect excess iron, but also inflammation or liver problems. High ferritin therefore does not automatically prove that the body has too much iron.

A clinician may interpret it alongside haemoglobin and other markers. The test provides information; it does not establish the cause of a symptom on its own.

Low iron stores and anaemia are not the same thing

Iron stores can fall before haemoglobin declines. Haemoglobin within the reference range therefore does not, by itself, rule out low stores. Ferritin and the blood count provide complementary information, interpreted alongside your health circumstances.

When deficiency is confirmed, its cause also matters: diet, blood loss or poor absorption may play a part. Mention heavy periods, digestive concerns and the medicines you use. Your clinician determines which investigations or treatment are needed; ferritin alone cannot reveal the source.

Where the body gets iron

Iron is found in meat, seafood, legumes and some fortified foods. Absorption varies by source: vitamin C helps the body absorb iron from plant foods.

Supplements are not harmless simply because they contain an essential mineral. Too much iron can be harmful, so its use needs a clear reason.

Before the test

Preparation may include a fasting requirement. Confirm the instructions for the tests you will have together and tell the laboratory which medicines or supplements you take.