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Biomarker library / Blood counts

Ferritin

Also called serum ferritin, iron stores test

Ferritin is the protein that stores iron, and the blood level tracks how much iron your body has in reserve. It is the standard first test for iron deficiency, the world's most common nutritional deficiency, and for suspected iron overload.

Written by the VitalDecades editorial team Reviewed by the editorial review process Updated

01  /  Reference ranges

What counts as normal

Scale in µg/L. Cut points from the sources listed below.
Population Apparently healthy adults and children 5+
Category Iron deficiency
Range under 15 µg/L Under 12 µg/L in children under 5.
Source WHO guideline on use of ferritin concentrations to assess iron status (2020)

Effective

Population Adults with infection or inflammation
Category May still indicate iron deficiency
Range under 70 µg/L Inflammation raises ferritin; WHO advises measuring an inflammation marker alongside.
Source WHO guideline on use of ferritin concentrations to assess iron status (2020)

Effective

Population Apparently healthy adult women (female)
Category Risk of iron overload
Range over 150 µg/L
Source WHO guideline on use of ferritin concentrations to assess iron status (2020)

Effective

Population Apparently healthy adult men (male)
Category Risk of iron overload
Range over 200 µg/L
Source WHO guideline on use of ferritin concentrations to assess iron status (2020)

Effective

Normal vs optimal

Lab "normal" ranges for ferritin are wide and vary by sex and lab. The WHO thresholds below are not a normal range; they are the cutoffs for iron deficiency and for risk of iron overload. A ferritin of 20 µg/L is above the deficiency cutoff and can still be low-normal iron stores; interpretation depends on symptoms, hemoglobin and inflammation.

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02  /  Why it matters

What the number tells you

Low ferritin means depleted iron stores, the stage before and during iron-deficiency anemia: fatigue, reduced exercise capacity, hair shedding and restless legs are common complaints. The catch is that ferritin is also an acute-phase protein: infection or inflammation raises it, which can hide a real deficiency. That is why the WHO sets a higher deficiency cutoff (under 70 µg/L) when inflammation is present and advises checking an inflammation marker alongside ferritin.

03  /  In practice

Testing and what moves it

When it is tested

  • Fatigue, anemia on a blood count, heavy menstrual bleeding, restless legs, notable hair shedding, or a vegetarian or vegan diet with symptoms.
  • With a marker of inflammation (such as CRP) when infection or inflammation is possible, per WHO.
  • Repeated high results, especially with a family history, prompt evaluation for iron overload (hereditary hemochromatosis).

What raises it

  • Infection and inflammation of any cause (ferritin is an acute-phase reactant), liver disease, alcohol.
  • True iron overload: hereditary hemochromatosis, repeated transfusions, high-dose iron supplementation.

What lowers it

  • Blood loss (menstrual, gastrointestinal), pregnancy demands, low dietary iron or poor absorption (celiac disease, bariatric surgery).
  • Frequent blood donation.

04  /  Related

Read next

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Frequently asked questions

What ferritin level means iron deficiency?

Under 15 µg/L in apparently healthy adults, per the WHO 2020 guideline. With infection or inflammation the cutoff rises to under 70 µg/L, because inflammation pushes ferritin up and can mask a deficiency.

Why do women ask about ferritin and hair loss?

Iron deficiency is a recognized contributor to diffuse hair shedding, and menstruating women are the group most likely to run low iron stores. A ferritin under the WHO cutoff with hair shedding is worth treating and re-testing; a mid-range ferritin usually is not the explanation.

My ferritin is high. Do I have hemochromatosis?

Not necessarily; infection, inflammation, liver disease and alcohol all raise ferritin. WHO flags risk of iron overload above 150 µg/L in healthy women and 200 µg/L in healthy men; the next step is usually transferrin saturation and, if that is high too, genetic testing.