Ferritin Blood Test

A ferritin blood test can help you:

• Detect low iron stores before or alongside iron deficiency anaemia.
• Explain symptoms such as fatigue, shortness of breath, hair shedding, or poor exercise tolerance.
• Monitor iron status if you have heavy periods, follow a plant based diet, are pregnant, or have gut conditions.
• Check whether iron supplementation is working and when iron stores have been refilled.
• Identify raised ferritin that may signal inflammation, liver disease, metabolic syndrome, or iron overload conditions such as haemochromatosis.

Ferritin is a hollow, spherical protein complex that stores iron atoms in a safe, soluble form inside cells, particularly in the liver, bone marrow, and spleen. It allows your body to stockpile iron and release it when needed for critical processes.

Iron is essential for:

• Making haemoglobin in red blood cells, which carries oxygen around the body.
• Supporting enzymes involved in energy production and metabolism.
• Maintaining healthy hair, skin, nails, and immune function.

A small amount of ferritin circulates in the blood. Blood ferritin levels usually reflect how much iron is stored in tissues, which is why ferritin is used as an indirect marker of body iron stores.

Ferritin's main role is iron storage and controlled release:

• When iron intake is adequate, ferritin stores surplus iron so it is available later and cannot generate excess oxidative stress.
• When iron intake is low or demand is high, ferritin releases iron back into the circulation for haemoglobin production and other uses.

If ferritin levels fall, it usually means iron stores are being depleted, often due to:

• Insufficient dietary iron.
• Increased needs, such as pregnancy or endurance training.
• Chronic blood loss, such as heavy periods or gastrointestinal bleeding.

If ferritin is raised, it can mean increased iron stores or an acute phase response, where ferritin rises in the context of inflammation, liver disease, infection, or metabolic stress.

Iron is central to oxygen transport and energy production, so ferritin and iron stores have a direct impact on how you feel day to day and on long term outcomes.

Low ferritin and low iron stores are associated with:

• Iron deficiency anaemia, causing tiredness, shortness of breath, palpitations, headaches, and reduced exercise capacity.
• Iron deficiency without anaemia, which can still cause fatigue, poor concentration, restless legs, and increased hair shedding.

High ferritin can be a marker for:

• Iron overload syndromes such as hereditary haemochromatosis, which can damage the liver, heart, joints, and pancreas over time.
• Chronic inflammation, liver disease, alcohol excess, or metabolic syndrome, where ferritin rises as part of a broader stress pattern.

Interpreting ferritin correctly helps guide safe iron supplementation, avoid unnecessary iron in people with high stores, and identify when further investigation is needed.

These tests are related but capture different parts of iron biology:

• Ferritin reflects iron stores, mainly in the liver and bone marrow.
• Haemoglobin measures the oxygen carrying protein in red blood cells and is used to diagnose anaemia.
• Serum iron measures iron circulating in the blood at a single point in time.
• Transferrin and transferrin saturation measure the main iron transport protein and how full it is with iron.

In practice:

• Low ferritin is often the earliest and most specific marker of iron deficiency.
• Haemoglobin can remain normal while ferritin is low, especially early on.
• Serum iron varies during the day and with meals, so it is less reliable alone.
• A full iron panel, including ferritin and transferrin saturation, gives the clearest picture in complex cases.

Ferritin is influenced by iron balance, inflammation, liver health, and lifestyle. Key factors include:

1. Iron intake and absorption

• Low intake of iron rich foods, especially in vegetarians, vegans, and people with overall low calorie intake, can reduce ferritin.
• Gut conditions such as coeliac disease, inflammatory bowel disease, gastric surgery, or low stomach acid can impair iron absorption.

2. Blood loss and increased demand

• Heavy menstrual periods, fibroids, endometriosis, and postpartum blood loss are common causes of low ferritin in women of reproductive age.
• Gastrointestinal bleeding from ulcers, polyps, cancers, or inflammatory conditions can deplete ferritin.
• Pregnancy, growth, and high intensity endurance training increase iron requirements.

3. Inflammation and chronic disease

• Ferritin is an acute phase reactant and can rise in infections, inflammatory diseases, liver disease, and some cancers.
• In these settings, a high ferritin does not necessarily mean iron overload, and other markers such as CRP and transferrin saturation help with interpretation.

4. Genetic and metabolic factors

• Hereditary haemochromatosis and other iron loading conditions can raise ferritin over time as iron accumulates.
• Metabolic syndrome, obesity, and non alcoholic fatty liver disease are often associated with moderately raised ferritin.

5. Alcohol and liver function

• Chronic high alcohol intake and liver injury can increase ferritin, as the liver is a major site of ferritin storage and production.

Yes. This is a common pattern, especially in early or mild iron deficiency.

You can have:

• Low ferritin indicating depleted iron stores.
• Normal haemoglobin and red blood cell indices on a full blood count.

In this situation:

• You may already have symptoms such as fatigue, reduced exercise tolerance, or hair shedding, even without diagnosed anaemia.
• Replenishing iron stores can prevent progression to iron deficiency anaemia and improve quality of life.

This is why ferritin is often used to investigate unexplained fatigue, especially in menstruating women, athletes, and people with restricted diets.

Reference ranges vary between laboratories and by sex and age. Typical adult ranges are often in the region of:

• Men: roughly 24 to 400 µg/L or ng/mL.
• Women: roughly 13 to 150 µg/L or ng/mL, with slightly different cut offs used by different labs.

Broadly:

• Low ferritin below the laboratory reference range almost always indicates depleted iron stores and, if low enough, iron deficiency.
• Ferritin in the low normal range may still be associated with symptoms in some people, especially if there is ongoing blood loss or high demand.
• High ferritin above the upper limit can reflect iron overload, inflammation, liver disease, or metabolic stress and requires context specific evaluation.

Fasting is not usually necessary for a ferritin test. You can typically have the test at any time of day.

If ferritin is being measured as part of a broader panel that includes fasting markers such as lipids or glucose, you may be asked to fast for those tests. Follow the instructions provided so that the whole panel is reliable.

Managing ferritin involves identifying the cause and correcting iron balance safely. Depending on your situation, clinician guided strategies may include:

• Increasing iron intake through diet, focusing on iron rich foods and combining them with vitamin C sources to enhance absorption.
• Using oral iron supplements in an appropriate dose and formulation when diet alone is insufficient, with follow up ferritin and full blood count to monitor response.
• Considering intravenous iron in certain cases, such as significant deficiency with intolerance to oral iron, malabsorption, or chronic inflammatory conditions.
• Investigating for sources of blood loss, such as heavy periods or gastrointestinal bleeding, if ferritin is low without obvious dietary causes.
• In cases of high ferritin, assessing for inflammation, liver disease, metabolic syndrome, and iron overload, and tailoring treatment accordingly, which may include lifestyle change, alcohol moderation, or venesection in iron loading conditions.