Biomarker · Nutrition
Ferritin
Ferritin reflects the body's iron stores. Learn what low and high ferritin can indicate, why inflammation matters and how the test is done.
Written by LON6EVITY Editorial Team · Last updated
Overview
Ferritin is a protein that stores iron inside cells. Small amounts circulate in the blood and reflect total iron stores.
Why it matters
Low ferritin is one of the earliest signs of iron deficiency, which can progress to iron-deficiency anaemia. High ferritin may point to iron overload, such as haemochromatosis, but is more often caused by inflammation, liver disease or other conditions.
Factors affecting the result
Ferritin is an acute-phase reactant — it rises with inflammation or infection. A 'normal' ferritin can therefore mask iron deficiency in someone with inflammation. Clinicians often interpret it alongside CRP, iron and transferrin saturation.
How the test is performed
A blood sample; some clinicians prefer a morning sample after fasting when iron tests are ordered together.
Reference ranges
Reference ranges and targets differ between laboratories, units and guidelines, and depend on age, sex, method and your overall clinical picture. A single result is not a diagnosis — interpret it with a qualified clinician. Ferritin ranges differ notably by sex and laboratory.
Factors that can affect the result
- Inflammation or infection
- Menstruation and pregnancy
- Liver disease
- Alcohol
- Iron supplements
Questions people commonly ask
- Can I have iron deficiency with normal ferritin?
- Yes, particularly when inflammation raises ferritin. Your clinician may look at additional iron markers.
Related biomarkers
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Understand your biomarkers in context
What does this mean for your own health data? Log your results, follow trends over time and bring an organised summary to your next doctor's appointment.
Sources
- Ferritin Blood Test. MedlinePlus, U.S. National Library of Medicine.