What my ferritin level actually tells me - when should I worry?
Written by Dr. Nitin Shori
Co-Founder and Chief Medical Officer, CoreVitals
MBBS • MRCGP • Active NHS GP partner
Published
18 December 2025
Read time: 12 minutes
Last reviewed
27 December 2025
Next review 27 March 2026
Short answer
Ferritin measures how much iron your body has in storage, so it is the clearest single indicator of your iron reserves. In most adults a result between roughly 30 and 300 ng/mL is normal, but the right level for you depends on your sex, any inflammation, and how you actually feel — one number rarely tells the whole story.
What ferritin actually measures
Ferritin is the protein your body uses to store iron and release it on demand. Because only a small, stable amount circulates in your bloodstream, a ferritin test is a reliable proxy for your total iron stores — far more so than measuring blood iron directly, which rises and falls with what you last ate. It is usually run as part of a wider iron panel alongside markers such as transferrin saturation.
What counts as a normal ferritin level?
Most laboratories report a normal range of roughly 30—300 ng/mL for men and 15—200 ng/mL for women, though reference ranges vary between labs. NICE treats a ferritin below 30 ng/mL as diagnostic of iron deficiency in most adults. Levels tend to sit higher after menopause and lower in pregnancy, so your result is always read against your own context rather than a single fixed cut-off.
When should a low ferritin worry you?
A low ferritin means your iron reserves are running down, and it is one of the most common abnormal results we see. Everyday causes include heavy periods, a diet low in absorbable iron, and reduced absorption in conditions such as coeliac disease. It is worth acting on when it comes with symptoms like persistent fatigue, breathlessness, hair thinning or restless legs — or when it appears alongside a low haemoglobin. Persistently low iron with no clear cause should always be investigated, not simply supplemented.
When should a high ferritin worry you?
A high ferritin is trickier to read, because ferritin also rises with inflammation, infection, liver strain and alcohol — so a single raised result more often reflects a temporary response than true iron overload. When it stays high, it is checked alongside transferrin saturation to rule out conditions such as haemochromatosis, an inherited tendency to absorb too much iron. The same number can be reassuring in one person and worth investigating in another.
How CoreVitals measures and interprets ferritin
CoreVitals includes ferritin as part of a full blood panel that also measures your complete iron profile, inflammatory markers and blood count — so a raised or lowered result is never read in isolation. Every result is reviewed by a clinician and returned with personalised interpretation and clear next steps, rather than just a number against a reference range. If something needs following up, we tell you what it means and what to do next.
Medically reviewed by Dr. Senan Alsanjari
Consultant Cardiac & Thoracic Radiologist
Level III Cardiac CT & MRI • NHS Consultant Radiologist, Frimley Park
Sources (4)
- National Institute for Health and Care Excellence (NICE) — Anaemia, iron deficiency: Clinical Knowledge Summary.
- British Society for Haematology — Guideline on the laboratory diagnosis and management of iron deficiency.
- World Health Organization — Serum ferritin concentrations for assessing iron status and iron deficiency.
- NHS — Haemochromatosis: overview, symptoms and treatment.
