Ferritin: Normal Range, High & Low Causes
What Ferritin measures
Ferritin stores iron inside cells, and a small amount circulates in the blood. A low level is the earliest and most specific sign of iron deficiency. Because inflammation raises ferritin, a normal or high value does not always rule out low iron.
Ferritin reference ranges
| Category | Conventional units | SI units |
|---|---|---|
| Adult men | 24 – 336 ng/mL | 24 – 336 µg/L |
| Adult women | 11 – 307 ng/mL | 11 – 307 µg/L |
| Suggests low iron stores | Below about 30 ng/mL | Below about 30 µg/L |
ng/mL and µg/L are the same number. Ranges vary widely between labs.
Common causes of a high result
- Inflammation or infection (ferritin is an acute-phase protein)
- Fatty liver or other liver disease
- Hemochromatosis or other iron overload
- Heavy alcohol use
- Obesity and metabolic syndrome
- Frequent blood transfusions
Common causes of a low result
- Iron deficiency from heavy periods, pregnancy or blood loss
- Low iron intake or poor absorption (celiac disease)
- Frequent blood donation
- Gastrointestinal bleeding
How to prepare for the test
Often tested after an overnight fast. Avoid iron supplements for 24 hours before, if your lab advises it.
How often to retest
About 8 to 12 weeks after starting iron, then as advised.
Track Ferritin over time
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Get the appFrequently asked questions
What is a normal ferritin level?
About 24–336 ng/mL for men and 11–307 ng/mL for women, though many clinicians treat below 30 ng/mL as low iron stores.
Can ferritin be normal while iron is low?
Yes. Inflammation raises ferritin, so clinicians may also check transferrin saturation and C-reactive protein.
Should I take iron if my ferritin is low?
Usually yes, but find the cause first, especially in men and postmenopausal women, because low iron can signal bleeding.
Related tests
Sources
This page is general education and was last updated 2026-10-30. It is not a substitute for medical advice. See our editorial approach.