Normal Ferritin Levels
Normal ferritin levels vary significantly by sex and age: approximately 135 μg/L for men, 43 μg/L for women, and 30 μg/L for children aged 6-24 months in the United States. 1
Sex-Specific Reference Ranges
Adult Men
- Average serum ferritin: 135 μg/L 1
- Upper limit of normal: approximately 193 ng/mL (mean 93 ng/mL) 2
- Research studies report geometric mean of 98 μg/L with 95% confidence range of 21-447 μg/L 3
- Another study reports mean of 69 ng/mL in normal men 4
Adult Women
- Average serum ferritin: 43 μg/L 1
- Upper limit of normal: approximately 146 ng/mL (mean 34 ng/mL) 2
- Non-menstruating women: 85 μg/L (26-279 μg/L range) 3
- Research reports mean of 35 ng/mL in normal women 4
Children
- Children aged 6-24 months: approximately 30 μg/L 1
Context-Dependent Interpretation
The interpretation of "normal" ferritin depends critically on the clinical context:
For Iron Deficiency Screening
- Ferritin <15 μg/L confirms iron deficiency in women of childbearing age (75% sensitivity, 98% specificity) 1
- Ferritin <12 μg/L has 61% sensitivity but 100% specificity for iron deficiency 1
- Recent evidence suggests higher thresholds may be more physiologically appropriate: <20 μg/L for children and <25 μg/L for non-pregnant women 5
- The AGA guidelines use <45 ng/mL as a threshold for iron deficiency (85% sensitivity, 92% specificity) 1
For Iron Overload/Hemochromatosis Screening
- Elevated ferritin defined as >300 μg/L in men and >200 μg/L in women when screening for hemochromatosis 1
- In hemochromatosis patients, ferritin >250 μg/L in men and >200 μg/L in women suggests iron overload 1
- Target ferritin during treatment of hemochromatosis: 50-100 μg/L 1
Important Clinical Caveats
Ferritin is an acute-phase reactant, meaning it can be falsely elevated independent of iron stores in several conditions 1:
- Chronic infection or inflammation (hepatitis, cirrhosis, neoplasia, arthritis) 1
- Tissue damage or organ disease 1
- Chronic kidney disease 1
- Malignancy 2
In inflammatory states, ferritin may be elevated despite depleted iron stores, masking true iron deficiency 1. In these situations, additional tests such as transferrin saturation, soluble transferrin receptor, or C-reactive protein should be used 1.
Methodological Considerations
Laboratory reference intervals may underestimate iron deficiency 6:
- Many published reference intervals have a lower limit of normal around 8-11 μg/L for women and 22-25 μg/L for men 6
- These intervals often fail to exclude individuals at risk for iron deficiency from the "normal" population 6
- Evidence-based clinical decision limits (>30 μg/L) may be more appropriate than traditional laboratory reference ranges for diagnosing iron deficiency 6