Ferritin
Ferritin is your body's iron-storage protein, and a blood ferritin test shows how much iron you have in reserve. It is the most useful single marker for spotting low iron stores, and it is usually done alongside other iron tests to build the full picture.
Standard Careof Australian women have depleted iron stores (ferritin below 30 µg/L), compared with 3.5% of men.
What is ferritin?
Ferritin is an iron-storage protein found mainly in the liver and in cells throughout your body. Your blood ferritin level mirrors how much iron you have in reserve — which is why it sits at the centre of the iron story. It is best read alongside the other iron studies: serum iron (the iron actually circulating in your blood), transferrin (the protein that carries iron through your blood), and transferrin saturation (how loaded that carrier is). One thing worth knowing: ferritin is also an acute-phase protein — meaning it rises with inflammation, infection, or illness, not just when iron is genuinely high. That nuance matters a lot for reading a result. Australia has no single harmonised reference interval for ferritin, and labs differ slightly by assay, so the range printed on your own report is the one that applies to you.
Why is it tested?
Ferritin is ordered to check your iron status. Most often it is part of an iron studies panel when someone has persistent tiredness, breathlessness, or unexplained anaemia — or when there is a concern that iron may be too high. In Australia, a ferritin below 30 µg/L is generally taken as a strong indicator of iron deficiency. Because ferritin rises with inflammation (it is an acute-phase protein), it is usually interpreted alongside the rest of the iron studies rather than in isolation. Your GP may also repeat it once any infection or illness has settled, since that gives a cleaner read on your true iron stores.
Reference range (Australia)
Australia has no single harmonised reference interval for ferritin and labs differ by assay, so use the range printed on your own report for the upper/normal limit. The clinically useful anchor is that a ferritin below 30 µg/L is generally a strong indicator of iron deficiency.
Reference intervals vary between laboratories. Always use the range printed on your own report.
What your result means
A low ferritin reflects depleted iron stores and is the most specific sign of iron deficiency. In Australia, a level below 30 µg/L is generally regarded as a strong indicator of iron deficiency. Common reasons include heavy menstrual periods (the most frequent cause in pre-menopausal women), a lower dietary iron intake (for example in a vegan or vegetarian diet), reduced absorption from conditions such as coeliac disease (an immune reaction to gluten that affects the small bowel), or blood loss from the gut. One catch: because ferritin is an acute-phase protein, inflammation can push it up even when iron is actually low — so a result that looks "normal" does not always rule iron deficiency out. Your GP can look at the rest of your iron studies to get the full picture.
Your ferritin sits within the range on your report, which suggests your iron stores are adequate. Keep in mind that ferritin can read normal even when iron is low if inflammation is present — your GP reads it alongside your symptoms and the other iron studies rather than in isolation. A varied diet with iron-rich foods helps support iron balance over time.
A high ferritin most often reflects inflammation rather than too much iron in your body. In fact, fewer than 1 in 10 cases of raised ferritin are due to genuine iron overload. Ferritin is an acute-phase protein — it commonly rises with infection, inflammation, obesity, liver conditions, or alcohol — and tends to come back down once the underlying issue settles. Less often, a high ferritin alongside a high transferrin saturation can point to genuine iron overload, such as haemochromatosis (an inherited condition where the body absorbs too much iron). Your GP will look at your transferrin saturation and other iron studies to tell these two patterns apart. They may also repeat the test once any infection clears to get a cleaner picture. Worth raising at your next appointment rather than reading too much into a single result.
What can affect your result
The biggest non-iron influence is inflammation. Infection, autoimmune conditions, obesity, liver disease, alcohol, and recent illness can all raise ferritin independently of your actual iron stores — which is exactly why it is read alongside the rest of the iron studies. On the side that lowers ferritin, anything that reduces iron absorption or increases blood loss can drag your stores down. Conditions such as coeliac disease affect how much iron your gut takes in; some long-term acid-suppressing medicines can also reduce absorption. Iron supplements and iron-containing multivitamins push ferritin up. Your GP weighs up your medications, your diet, and any inflammation when interpreting the result.
When to act
If your ferritin is outside the range on your report, that is worth a conversation with your GP. They will read it together with your serum iron, transferrin, and transferrin saturation, alongside your symptoms, any signs of inflammation, and your medications — to work out whether the result reflects genuinely low or high iron stores, or simply an inflammation effect. A trend over time is usually more informative than a single number on its own. This page is general information and is not a substitute for advice from your GP.
Frequently asked questions
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