What should you know about ferritin blood test?

Ferritin is a protein that stores iron. A low result can support iron deficiency and may occur with blood loss, low dietary intake, or reduced absorption. A high result does not automatically mean excess iron: infection, inflammation, liver problems, and some other illnesses can raise ferritin.

Clinicians often compare ferritin with a full blood count and iron-related tests. Fatigue, breathlessness, pale skin, restless legs, or reduced concentration may occur with iron deficiency, but these symptoms have many causes. The result is one part of the clinical picture.

Ask whether you need to fast or pause any supplement; follow the instructions from the testing service. Tell the clinician about heavy periods, digestive symptoms, recent infection, liver disease, kidney disease, and iron tablets or infusions.

Do not start high-dose iron solely from a result without advice. Follow-up may look for the reason for low iron, such as bleeding or poor absorption. Conditions such as [Anaemia](/conditions/anaemia/), [Coeliac Disease](/conditions/coeliac-disease/), [Crohn's Disease](/conditions/crohns-disease/), or [Chronic Kidney Disease](/conditions/chronic-kidney-disease/) can change how results are understood.

Arrange medical review for persistent fatigue, breathlessness, palpitations, fainting, black or bloody stools, or unusually heavy bleeding. Seek urgent help for severe breathlessness, chest pain, collapse, or confusion. Fever or feeling acutely unwell can also affect ferritin and should be discussed rather than interpreted in isolation.

Ask what your ferritin means alongside your blood count, whether inflammation could affect it, and whether repeat testing or iron studies are needed. Ask what source of iron loss or poor absorption should be investigated.