What is ferritin and why does it matter for iron and energy levels? What high and low results can mean, and how it differs from a standard full blood count.
Ferritin is the protein your body uses to store iron. A ferritin blood test is one of the most useful ways to assess your iron status, because it can pick up low iron stores before you become anaemic, making it a valuable early marker for anyone with symptoms like fatigue, breathlessness, or hair thinning.
Why does ferritin matter?
Iron is essential for making haemoglobin, the protein in red blood cells that carries oxygen around your body. Ferritin reflects how much iron you have stored in reserve. Because your body draws on these stores before your red blood cells are affected, ferritin often falls first; sometimes causing symptoms of low iron even while your full blood count still looks normal.
What does low ferritin mean?
Low ferritin indicates depleted iron stores, and is a common cause of fatigue, breathlessness on exertion, pale skin, brittle nails, and hair thinning. It’s particularly common in:
- Women with heavy periods.
- People following vegetarian or vegan diets.
- Those with digestive conditions affecting iron absorption.
- Endurance athletes and frequent blood donors.
- Pregnant women.
What does high ferritin mean?
High ferritin can indicate excess iron storage, but it can also rise simply because ferritin behaves as an “acute phase” marker, meaning it increases with inflammation, infection, or liver conditions, regardless of your actual iron levels. This is why a raised ferritin is usually interpreted alongside other markers like CRP (inflammation) and full iron studies, rather than in isolation.
Ferritin vs a full blood count: what’s the difference?
A full blood count (FBC) tells you whether you’re currently anaemic; that is, whether your red blood cells or haemoglobin are already low. Ferritin tells you about your iron reserves, which can be depleted well before anaemia develops. Testing both together gives a much clearer picture of your iron status than either alone.
When should you test your ferritin?
Consider testing if you have persistent fatigue, breathlessness, hair thinning, restless legs, pale skin, or you’re in a higher-risk group such as those with heavy periods or a plant-based diet. Ferritin is included in our General Health & Wellbeing Screen and our Vitamin & Mineral Deficiency Test.
Not sure which test to choose? Use our free Test Finder for a personalised recommendation in under a minute.
Frequently asked questions
Can ferritin be low even if I’m not anaemic?
Yes; this is one of the most useful things about the test. Ferritin often falls before anaemia develops, so it can catch depleted iron stores early.
Why might my ferritin be high but I don’t have too much iron?
Ferritin rises with inflammation and infection, independent of iron levels, which is why raised results are interpreted alongside markers like CRP.
Should vegetarians and vegans test ferritin regularly?
It can be worthwhile, since plant-based diets carry a higher risk of low iron stores, especially alongside symptoms like fatigue.
Do I need to fast for a ferritin test?
No fasting is generally required, though we’ll confirm this when you book if it’s part of a wider panel.
How quickly will I get my results?
Most results are available within 1–2 working days and are reviewed by a GMC-registered doctor before you receive them.
Important note
This article is for general education only and is not medical advice or a diagnosis. Reference ranges vary between laboratories, and any abnormal result should be discussed with your GP or a qualified clinician. Trupoint Health blood tests are analysed by a UKAS-accredited laboratory and reviewed by a GMC-registered doctor.
Medically reviewed by: ____________ (GMC-registered), pending review.
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