Ferritin Blood Test: Normal Ranges, Causes & What Your Results Mean

What Is Ferritin?

Ferritin is the body's primary iron storage protein. Each ferritin molecule can hold up to 4,500 iron atoms in its hollow spherical shell, safely sequestering iron that would otherwise be toxic to cells. The small amount of ferritin that circulates in the blood directly reflects the body's total iron stores, making it the single most useful test for diagnosing iron deficiency.

Iron is essential for haemoglobin production, oxygen transport, energy metabolism, and DNA synthesis. The body carefully regulates iron absorption from the gut because there is no active excretion mechanism — once absorbed, iron is either used, stored as ferritin (mainly in the liver, spleen, and bone marrow), or lost through bleeding, skin cell shedding, or menstruation.

Importantly, ferritin is also an acute-phase reactant, meaning it rises during inflammation, infection, and liver disease — potentially masking underlying iron deficiency. This is why ferritin should always be interpreted alongside transferrin saturation and a full blood count.

Why Is Ferritin Tested?

• Iron deficiency screening — ferritin below 30 µg/L is diagnostic of depleted iron stores, even before anaemia develops
• Anaemia investigation — distinguishing iron-deficiency anaemia from other causes
• Iron overload disorders — hereditary haemochromatosis causes progressive iron accumulation
• Chronic fatigue evaluation — low ferritin is one of the most common treatable causes of fatigue, especially in women
• Monitoring iron therapy — tracking ferritin during oral or intravenous iron supplementation
• Inflammation assessment — as an acute-phase reactant, elevated ferritin can indicate systemic inflammation

Normal Ranges

Many functional medicine practitioners consider optimal ferritin to be 40–100 µg/L. Levels below 30 µg/L indicate depleted stores even without anaemia. NICE recommends investigating ferritin above 300 µg/L in men or 200 µg/L in women for possible haemochromatosis.

What Do High Ferritin Levels Mean?

• Hereditary haemochromatosis — the most common genetic disorder in Northern Europeans; iron accumulates in the liver, heart, and pancreas
• Inflammation or infection — any inflammatory condition raises ferritin as part of the acute-phase response
• Liver disease — hepatitis, fatty liver disease, and cirrhosis release stored ferritin
• Alcohol excess — even moderate alcohol intake can elevate ferritin
• Metabolic syndrome — insulin resistance is associated with elevated ferritin
• Blood transfusions — repeated transfusions cause iron loading
• Malignancy — some cancers produce ferritin as a tumour marker

What Do Low Ferritin Levels Mean?

• Iron deficiency — the most common nutritional deficiency worldwide; ferritin drops before haemoglobin
• Heavy menstruation — the leading cause of iron depletion in pre-menopausal women
• Gastrointestinal blood loss — coeliac disease, inflammatory bowel disease, peptic ulcers, or colorectal cancer
• Inadequate dietary intake — vegetarians and vegans are at higher risk without careful planning
• Pregnancy — increased iron demands for foetal development
• Intense exercise — endurance athletes experience foot-strike haemolysis, sweat losses, and GI bleeding
• Malabsorption — coeliac disease, gastric bypass surgery, or H. pylori infection impair iron absorption

How to Improve Your Ferritin Levels

• Iron-rich foods — red meat, liver, shellfish (haem iron) are absorbed 2–3 times more efficiently than plant sources (lentils, spinach, fortified cereals)
• Vitamin C pairing — consume vitamin C-rich foods (citrus, peppers, tomatoes) alongside iron-rich meals to enhance absorption
• Avoid tea and coffee with meals — tannins and polyphenols inhibit iron absorption by up to 60%
• Consider supplementation — if ferritin is below 30 µg/L, discuss oral iron (ferrous fumarate 210mg, often prescribed by GPs) or IV iron for severe deficiency
• If ferritin is too high — reduce alcohol, treat underlying liver disease, and if haemochromatosis is confirmed, therapeutic venesection (blood removal) is the standard treatment
• Retest after 3 months — ferritin takes 8–12 weeks to respond to supplementation

When Should You Get Tested?

• You feel persistently tired, dizzy, or short of breath
• You have heavy periods or are pregnant
• You follow a vegetarian or vegan diet
• You are an endurance athlete experiencing declining performance
• You have a family history of haemochromatosis
• You have unexplained hair loss or restless legs

Which Lola Health Tests Include Ferritin?

Ferritin is included in Core Health, Vital Check, and Peak Insights. For a full iron panel, pair with iron, TIBC, and transferrin saturation. Available as an add-on with any Lola Health blood test.