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What does a high or low ferritin mean?

Last updated: 24 September 2026

Ferritin tracker

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Ferritin is a protein that stores iron, and the blood test measures how much of it is circulating. It is the closest thing to a fuel gauge for your iron reserves: it usually drops before you become anaemic, which is why it gets checked when someone is tired, losing hair, or donating blood regularly.

It is also an acute phase reactant, meaning it rises with inflammation regardless of iron. That single fact explains most confusing ferritin results, and it is why the number is rarely interpreted on its own.

Typical ferritin ranges

Ranges vary between laboratories, and the range printed on your own report is the one that applies to your sample. Some labs report in µg/L, which is the same number as ng/mL.

GroupCommonly reported range
Menabout 24–336 ng/mL
Womenabout 11–307 ng/mL
Iron deficiency likelybelow 30 ng/mL
Iron deficiency, with inflammation presentcan still be below 100 ng/mL

What a low ferritin can mean

A low ferritin means depleted iron stores, and it has a cause worth finding rather than just correcting. Common ones include heavy menstrual bleeding, pregnancy, a diet low in absorbable iron, coeliac disease or another absorption problem, and bleeding somewhere in the gut.

You can have a low ferritin with a completely normal haemoglobin. That is early iron deficiency, before it becomes anaemia, and it is often the stage at which people feel tired without knowing why.

What a high ferritin can mean

Why one ferritin result is hard to read

Because inflammation pushes ferritin up and iron deficiency pulls it down, a single mid-range result can hide either. Someone with low iron stores and an ongoing inflammatory condition can land at 80 ng/mL and look unremarkable.

This is the case for tracking it rather than checking it once. A ferritin that has fallen from 120 to 45 over two years is telling you something that 45 on its own does not, even though both readings sit inside the printed range.

When to talk to a doctor

Any result outside your lab’s range is worth a conversation, and so is a result inside the range that has moved a long way from your own baseline. Get seen promptly if a low ferritin comes with breathlessness, chest pain, or unusually heavy periods, or if a high ferritin comes with joint pain, abdominal pain, or a family history of haemochromatosis.

Common questions

Is ferritin the same as iron?

No. Serum iron is how much iron is in your blood right now, which swings through the day and with meals. Ferritin reflects what is in storage, which is why it is the better measure of long-term iron status.

Can ferritin be low if my haemoglobin is normal?

Yes, and it commonly is. Iron stores empty before red blood cell production suffers, so ferritin falls first. A normal full blood count does not rule out iron deficiency.

How quickly does ferritin change?

Slowly. Meaningful movement takes weeks to months, so retesting sooner than about three months after a change rarely shows anything useful. Inflammation, by contrast, can raise it within days.

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