Blood ferritin: what low and high ferritin mean

Ferritin is a protein in which the body stores iron, and its blood level shows how much iron is held in reserve. It is the most useful individual test for detecting iron deficiency because ferritin falls even before anaemia develops. Raised ferritin does not always mean excess iron: it also rises with inflammation, liver disease and excessive alcohol consumption.

Who the test is for

• people with fatigue, breathlessness on exertion, palpitations, pallor, increased hair loss or restless legs,
• people whose blood count shows anaemia or small red blood cells (low MCV),
• women with heavy periods and pregnant women,
• vegetarians, vegans and regular blood donors,
• people with coeliac disease or inflammatory bowel disease,
• people with suspected iron overload, for example if someone in the family has haemochromatosis,
• people being treated for iron deficiency or excess, to monitor treatment.

What ferritin is and what it shows

Most ferritin is found in the liver, spleen and bone marrow, where it stores iron for haemoglobin production. There is little in the blood, but that amount reflects the size of the stores: as they are depleted, ferritin falls before haemoglobin.

Ferritin is also an acute-phase reactant: it rises with inflammation and infection regardless of iron stores, and is also raised with liver damage. Results are therefore interpreted alongside CRP and other iron indicators.

Panels including this test

Test Ferritin is also included in this panel.

Iron panelCBC, iron, UIBC TIBC, ferritin30.00€Details ›

All panels including Ferritin (10) ›

Preparation and sample

Ferritin is measured in venous blood, and you do not need to fast for this test alone.

If serum iron is also being measured alongside ferritin, as in the iron panel, come in the morning fasting, preferably between 7 and 10, because blood iron levels vary during the day. If serum iron is also being measured alongside ferritin, do not take iron tablets or syrup for 24 hours before blood collection unless your doctor has told you otherwise. If you have recently had an infection or an iron infusion, tell the blood collection staff and your doctor, because both temporarily raise ferritin.

How to interpret a ferritin result

Ferritin is expressed in µg/L (the same as ng/mL). The reference interval depends on sex, age and method and is printed on your report. A doctor interprets the result alongside symptoms, the blood count and other iron indicators.

Low ferritin: iron deficiency

Low ferritin means iron stores are reduced. In adults, a level below 30 µg/L generally confirms iron deficiency, while below 15 µg/L the stores are practically depleted. The lower limit of the reference interval on the report, particularly for women, is often below 30 µg/L, so even a value within the interval may mean reduced stores.

The most common causes are blood loss (heavy periods, gastrointestinal bleeding), increased requirements during pregnancy and growth, too little dietary iron and reduced absorption, for example with coeliac disease or after stomach surgery.

Older age alone does not cause low ferritin. After menopause, when monthly blood loss stops, ferritin is on average higher than before. Low ferritin in men and postmenopausal women is therefore not attributed to age; its cause is investigated, particularly hidden gastrointestinal bleeding. A doctor decides on iron replacement; read more in the article on iron-deficiency anaemia.

Normal ferritin during inflammation does not rule out deficiency

With inflammation, infection or chronic disease, ferritin rises and can therefore be normal even when stores are low. In an adult with anaemia and an inflammatory disease, ferritin between 30 and 100 µg/L may still mean iron deficiency. It is therefore useful to measure inflammatory markers, alongside ferritin, and a doctor may repeat ferritin measured during an acute infection after recovery.

Raised ferritin

Raised ferritin is most often not a sign of excess iron. More common causes are inflammation and infection, liver disease including fatty liver, excessive alcohol consumption and metabolic syndrome. Less often, it reflects iron overload, for example hereditary haemochromatosis, when the body absorbs too much iron from food, after frequent transfusions or due to excessive iron supplementation. An overactive thyroid and some blood disorders also raise ferritin.

The next investigative step is usually transferrin saturation, which a doctor calculates from serum iron and TIBC:

Result	What it most often means
raised ferritin, normal transferrin saturation	inflammation, liver disease, alcohol or metabolic syndrome; usually followed by liver function tests, CRP, glucose and blood lipids
raised ferritin and raised transferrin saturation	possible iron overload; further investigation is required, including genetic testing for haemochromatosis

Ferritin or the full iron panel?

Without inflammation, ferritin alone is usually enough to assess stores, while a more complete picture is provided by the Ferro (iron) panel. In addition to ferritin, it includes a complete blood count (CBC), which shows whether anaemia is present, serum iron and TIBC and UIBC, which indicate how much iron can be bound by transferrin, the protein that transports it in the blood. Together, they help distinguish iron deficiency from inflammation and identify iron overload.

How to arrange testing

You can have blood taken without an appointment or referral at one of our branches across Croatia (listed under Contact). CRP can also be measured alongside ferritin, and prices for all tests and panels are available in the service price list. Take the results to the doctor who recommended the test.

Frequently asked questions

Is ferritin a tumour marker?

No. Ferritin is not used to detect cancer. It may be raised in some malignancies, such as lymphoma and leukaemia, but much more often rises because of inflammation, liver disease or alcohol, so it does not by itself indicate a tumour. We explain the purpose of tumour markers, in a separate article.

Can ferritin be low while the blood count is normal?

Yes. This is iron deficiency without anaemia: stores have been depleted, but haemoglobin is still within range. A doctor will assess whether replacement is needed and what has caused the deficiency.

Why is ferritin high but iron low?

This pattern most often accompanies inflammation or chronic disease: the body retains iron in storage, leaving less in the blood while ferritin rises. It may be anaemia of chronic disease or iron deficiency masked by inflammation, which a doctor distinguishes using TIBC, transferrin saturation and CRP.