Iron & ferritin, explained
Ferritin shows your iron stores; transferrin saturation shows how much is in use. We read them together with CRP, because inflammation can hide a low ferritin.
Three things we do that a printed range doesn’t
Ranges change with both. We use the set for you — 26 range sets in total.
Ferritin is read with CRP: inflammation raises ferritin and can hide a real deficiency.
WHO, IFCC-EFLM, EASL. Organisation, document, year.
Ferritin — the ranges we use
WHO: a low level means depleted stores (fatigue, reduced performance); during inflammation it is falsely elevated.
| Rating | Range | What it means |
|---|---|---|
| Talk to a doctor | below 15 µg/L | |
| Worth improving | 15 – 30 µg/L | |
| Good | 30 – 200 µg/L | Iron stores within range. |
| Worth improving | 200 µg/L and above |
This marker also has 2 age- or sex-specific range sets in the app — the table shows the general one.
Articles in this guide
- Ferritin and iron: what the values mean and how to improve themMarker explained
- How to raise iron and ferritin: an action planHow to improve
- AI blood test analyzer: what it can and cannot do (and how to use ChatGPT safely)Reading your report
- Blood test reference values — table by test for adultsReading your report
- Blood tests before pregnancy: what to check before you conceiveLife stages
- ChatGPT prompt for blood test results: a safe template and what to checkReading your report
- Fatigue: which blood tests explain it — and which don'tSymptom → test
- Hair loss: which blood tests reveal the cause — and when they do notSymptom → test
This content is for information only and is not a substitute for medical advice. Talk to your doctor about your results.
Good to know
Ferritin 18 — should I be worried?
Upload your report and you’ll see the answer for your exact value, age and sex — with the source of the range. In general: one value outside the printed range is rarely an emergency; the pattern and the trend matter more.
Do I need a new test?
No. Upload the one you already have. If a re-test is useful, the plan tells you when.
Is this a diagnosis?
No. It is an explanation to help you and your doctor. When a value needs a doctor, we say so.