Serum Ferritin Reference Range
The normal reference range for serum ferritin in healthy adults is approximately 15-30 μg/L as the lower limit and extends to 200-400 μg/L as the upper limit, with significant sex differences: men typically range from 20-400 μg/L and women from 15-200 μg/L, though these values increase substantially after menopause in women.
Normal Reference Ranges
Standard Laboratory Values
The lower limit of normal for most laboratories lies in the 15-30 μg/L range 1. However, recent large-scale studies suggest:
- Men: 23-741 μg/L (older adults) 2 or 23-396 μg/L (general population) 3
- Women ≤50 years: 19-440 μg/L 2 or 10-300 μg/L 3
- Women >50 years: 36-507 μg/L 4
Age and Sex Considerations
Ferritin levels show distinct patterns:
- Males: Median increases from 23 μg/L at ages 12-16 years to plateau around 120 μg/L after age 32 5
- Premenopausal women: Remain in the 30s μg/L range 5
- Postmenopausal women: Rise to approximately 80 μg/L 5, reflecting cessation of menstrual blood loss
Low Ferritin Values Indicate
Iron Deficiency Thresholds
Ferritin <15 μg/L is highly specific (99%) for absent iron stores 1. However, clinical decision-making should use higher thresholds:
- <30 μg/L: Generally indicative of low body iron stores 1
- <45 μg/L: Optimal trade-off between sensitivity (85%) and specificity (92%) for diagnosing iron deficiency 6, 1
The traditional threshold of <15 μg/L has only 59% sensitivity, missing many cases of iron deficiency 6. Using the 45 μg/L threshold maximizes detection while maintaining acceptable specificity.
Clinical Consequences of Low Ferritin
In older men, low ferritin levels are associated with:
- Increased major hemorrhage risk (HR 1.51) 2
- Increased GI bleeding (HR 2.03) 2
- Increased GI cancer risk (HR 1.27) 2
High Ferritin Values Indicate
Upper Limit Interpretation
Ferritin >150 μg/L is unlikely to occur with absolute iron deficiency, even with inflammation present 1. Elevated ferritin suggests:
- Iron overload (hemochromatosis, repeated transfusions)
- Acute or chronic inflammation (ferritin is an acute phase reactant)
- Liver disease
- Malignancy
- Metabolic syndrome
Critical Caveat: Inflammation
Ferritin is an acute phase protein that becomes falsely elevated during inflammation, masking true iron deficiency 1, 7. In inflammatory conditions (IBD, CHF, CKD):
- Standard threshold <30 μg/L does not apply 7
- Use <100 μg/L as the threshold for iron deficiency 7
- If ferritin is 100-300 μg/L, transferrin saturation <20% confirms iron deficiency 7
- Consider adjunctive tests: serum iron, transferrin saturation, C-reactive protein 6
This is crucial because proinflammatory cytokines increase hepcidin, which sequesters iron in storage sites despite normal or high ferritin levels, creating functional iron deficiency 7.
Practical Algorithm
For otherwise healthy adults:
- Ferritin <45 μg/L → Investigate for iron deficiency and underlying causes
- Ferritin 45-150 μg/L → Normal range (sex and age dependent)
- Ferritin >150 μg/L → Consider iron overload, inflammation, or other pathology
For patients with chronic inflammatory conditions:
- Ferritin <100 μg/L → Iron deficiency present
- Ferritin 100-300 μg/L + transferrin saturation <20% → Iron deficiency present
- Ferritin >300 μg/L → Iron deficiency unlikely