Normal Ferritin Levels in Adults
The normal serum ferritin range in adults is 20-250 μg/L for men and 20-200 μg/L for women, though most laboratories report lower limits of normal in the range of 15-30 μg/L. 1
Standard Reference Ranges by Sex
- Men: Normal range is 20-250 μg/L according to ESPEN guidelines 1
- Women: Normal range is 20-200 μg/L according to ESPEN guidelines 1
- Alternative reference values from AASLD suggest slightly narrower ranges: 20-200 μg/L for men and 15-150 μg/L for women 1
The lower limit of normal for most clinical laboratories falls between 15-30 μg/L, though this threshold is problematic for clinical decision-making 2.
Critical Clinical Thresholds for Interpretation
Understanding ferritin levels requires moving beyond simple "normal ranges" to clinically meaningful thresholds:
Iron Deficiency Thresholds
- Ferritin <15 μg/L: Highly specific (99% specificity) for absolute iron deficiency and indicates absent iron stores 2, 1
- Ferritin <30 μg/L: Generally indicates low body iron stores and warrants clinical attention 2
- Ferritin <45 μg/L: Provides optimal sensitivity-specificity balance (92% specificity) for iron deficiency in clinical practice, particularly when chronic inflammation may be present 2
Upper Limit Considerations
- Ferritin >150 μg/L: Unlikely to occur with absolute iron deficiency, even in the presence of inflammation 2
- Ferritin >1000 μg/L: When accompanied by elevated liver enzymes, predicts cirrhosis in 80% of hemochromatosis patients 1
Essential Caveats for Clinical Interpretation
Ferritin is an acute-phase protein that rises during inflammation, infection, or tissue damage, potentially masking depleted iron stores. 2 This is the most critical pitfall in ferritin interpretation.
Adjusting Thresholds in Inflammatory States
- In patients with chronic inflammatory conditions (IBD, chronic kidney disease, heart failure, malignancy), the threshold for iron deficiency shifts upward to ferritin <100 μg/L 2
- A ferritin cut-off of 45 μg/L provides respectable specificity (0.92) when chronic inflammatory processes are present 2
Never Interpret Ferritin in Isolation
- Always evaluate ferritin alongside transferrin saturation (TSAT) and clinical context 1
- The combination of low ferritin with low TSAT (<20%) confirms absolute iron deficiency 2
- Normal or elevated ferritin with low TSAT suggests functional iron deficiency or anemia of chronic disease 2
Quantitative Relationship to Iron Stores
- Each 1 μg/L of serum ferritin corresponds to approximately 10 mg of stored iron in the body 1
- This direct relationship makes ferritin the most specific indicator of depleted iron stores in the absence of inflammation 2
Common Clinical Pitfalls to Avoid
Do not rely on laboratory-reported "normal ranges" alone. A systematic review found that ferritin reference intervals are often based on studies with high risk of bias, frequently including individuals at risk for iron deficiency in the "normal" population sample 3. The median lower limit of normal from literature review was only 8 μg/L in females and 25 μg/L in males 3, which are too low for optimal clinical decision-making.
Do not dismiss symptoms in patients with ferritin 15-45 μg/L simply because it falls within the "normal range." These patients have depleted iron stores and may experience fatigue, reduced exercise tolerance, and other symptoms even before anemia develops 2.