Normal Serum Ferritin Reference Ranges in Adults
The normal serum ferritin reference range is 20-250 μg/L for adult men and 20-200 μg/L for adult women, according to the 2022 ESPEN micronutrient guideline. 1
Standard Reference Intervals by Sex
- Adult men: 20-250 μg/L is the established reference range 1
- Adult women: 20-200 μg/L is the established reference range 1
The ESPEN guideline provides a slightly broader reference range (24-336 μg/L for men and 11-307 μg/L for women) when accounting for methodological variability across different laboratory assays 1
Average Values in Healthy Populations
- Men: The average serum ferritin in healthy adult men is approximately 93-135 μg/L 2, 3
- Women: The average serum ferritin in healthy adult women is approximately 34-43 μg/L 2, 3
These averages fall well within the reference ranges but demonstrate the substantial sex difference in iron stores, with men typically having 2-3 times higher ferritin levels than premenopausal women 2, 3
Critical Clinical Thresholds for Interpretation
Ferritin <15 μg/L has 99% specificity for absolute iron deficiency, making it the gold standard threshold for diagnosing depleted iron stores 4, 2
Additional clinically relevant thresholds include:
- <30 μg/L: Generally indicates low body iron stores and warrants treatment consideration 2
- <45 μg/L: Provides optimal sensitivity-specificity balance (92% specificity) for clinical decision-making and may justify gastrointestinal investigation 4, 2
- >150 μg/L: Rarely occurs with absolute iron deficiency, even in the presence of inflammation 2
- >1000 μg/L: When accompanied by elevated liver enzymes, predicts cirrhosis in 80% of hemochromatosis patients 4
Essential Caveats for Clinical Practice
Ferritin is an acute-phase reactant that rises during inflammation, infection, or tissue damage, potentially masking depleted iron stores. 1, 2 This is the single most important pitfall in ferritin interpretation.
- In inflammatory conditions, the threshold for iron deficiency shifts upward to ferritin <100 μg/L 2
- Ferritin can be falsely elevated in malignancy, hepatitis, cirrhosis, and chronic inflammatory states 3, 5
- Never interpret ferritin in isolation—always evaluate alongside transferrin saturation and clinical context 4, 2
Methodological Variability Across Laboratories
No generic reference ranges are universally agreed upon due to variability in immunological methods for determining serum ferritin. 1 Laboratories using commercial methods should indicate their own reference ranges, which may differ slightly from the ESPEN standard 1
The relationship between serum ferritin and stored iron is direct: 1 μg/L of serum ferritin equals approximately 10 mg of stored iron in the absence of inflammation 2