Ferritin

What is ferritin?

Ferritin is a protein that stores iron in your cells, primarily in the liver, spleen, bone marrow, and skeletal muscle. A small amount of ferritin circulates in the bloodstream, and measuring this serum ferritin level gives a reliable indication of total body iron stores.

Of all the iron markers available — serum iron, transferrin, TIBC (total iron binding capacity) — ferritin is the most clinically sensitive for detecting iron deficiency in its earliest stage. Stores become depleted in the ferritin compartment first; only later does serum iron fall, and later still does haemoglobin drop. This means that a low ferritin can identify iron deficiency weeks or months before a standard haemoglobin test would detect anything abnormal.

This matters practically: iron deficiency without anaemia is a common and underrecognised cause of fatigue, poor concentration, hair loss, restless legs, and reduced exercise tolerance — particularly in women of childbearing age, vegetarians, and athletes. Testing ferritin rather than relying on haemoglobin alone is essential for catching this stage.

Ferritin is also an acute-phase reactant, meaning it rises non-specifically in inflammation, infection, liver disease, and malignancy, which can mask coexisting iron deficiency. Interpreting ferritin alongside CRP (C-Reactive Protein) allows clinicians to account for this effect.

Normal reference range

• Adult males: 30–300 µg/L
• Adult females: 15–200 µg/L

Important: Reference ranges vary between laboratories and depend on individual factors including age, sex, pregnancy status, and medication. Always interpret your result in the context of a clinician review. The Vesey reviews every result before release.

What a high ferritin may indicate

An elevated ferritin result requires careful interpretation because it can reflect iron overload or simply an acute inflammatory or liver response. Possible causes include:

• Hereditary haemochromatosis — the most important cause of true iron overload; excess iron deposits in the liver, heart, joints, and pancreas over time
• Infection and acute inflammation — ferritin rises as part of the body's acute-phase response; CRP is usually also elevated
• Liver disease — ferritin is released from damaged liver cells (alcoholic liver disease, NAFLD, viral hepatitis)
• Malignancy — certain cancers (leukaemia, lymphoma, hepatocellular carcinoma) cause marked ferritin elevation
• Metabolic syndrome and obesity — chronically elevated ferritin is associated with insulin resistance and visceral adiposity
• Regular blood transfusions — transfused iron accumulates if not excreted
• Adult-onset Still's disease — characteristically causes very high ferritin in the context of fever and joint pain

What a low ferritin may indicate

A low ferritin almost always indicates depleted iron stores, regardless of haemoglobin. Common causes include:

• Inadequate dietary iron — particularly in those following vegetarian or vegan diets (plant iron is less bioavailable)
• Heavy menstrual bleeding — the commonest cause of iron deficiency in pre-menopausal women
• Gastrointestinal blood loss — from peptic ulcers, NSAIDs, bowel cancer, or inflammatory bowel disease
• Malabsorption — coeliac disease and other small bowel conditions reduce iron absorption
• Pregnancy and breastfeeding — greatly increased iron demands frequently deplete stores
• Endurance athletes — increased losses via sweat, gut, and foot-strike haemolysis in runners

Get tested at The Vesey, Sutton Coldfield

Ferritin is included in the following panels at The Vesey Private Hospital:

• Anaemia Profile — ferritin, haemoglobin, B12, folate, and iron studies
• Nutritional Health panel — ferritin plus key vitamins and minerals
• Iron Status panel — ferritin, serum iron, TIBC, transferrin saturation
• Lifestyle Screen — broad health check including ferritin

Results are reviewed by a clinician before secure release, typically within 24 hours. Appointments available Monday–Saturday in Sutton Coldfield.

Frequently asked questions

What is a normal ferritin level?

Normal ferritin is 30–300 µg/L for adult males and 15–200 µg/L for adult females. A low ferritin is the earliest and most sensitive indicator of depleted iron stores, even before haemoglobin falls below the normal range.

Can I have iron deficiency with a normal haemoglobin?

Yes. Ferritin can be significantly depleted before haemoglobin falls — a stage called iron depletion. This commonly causes fatigue, hair loss, and poor concentration even when a full blood count appears normal. Ferritin is the only way to detect this.

What does a high ferritin mean?

High ferritin can reflect iron overload (haemochromatosis) or be a non-specific acute-phase response to infection, inflammation, liver disease, or malignancy. Transferrin saturation is measured alongside to distinguish true iron overload from inflammatory elevation.

Why is ferritin better than serum iron for detecting deficiency?

Serum iron fluctuates significantly throughout the day and is affected by recent food intake. Ferritin is more stable and reflects accumulated iron stores over time, making it the more reliable indicator. It falls before serum iron becomes abnormal.

Do I need to fast before a ferritin test?

Fasting is not strictly required for ferritin alone. However, if your ferritin is being tested as part of a comprehensive iron panel or alongside fasting glucose and cholesterol, your clinician may recommend an overnight fast. We will advise at the time of booking.