Normal Ferritin Levels for Women
The normal ferritin level for women is 20-200 μg/L, with an average of 43 μg/L in the United States. 1 However, recent evidence suggests that current reference ranges may lead to underdiagnosis of iron deficiency in women.
Standard Reference Ranges
According to established guidelines, ferritin reference ranges for women are:
- CDC Guidelines: Average serum ferritin concentration for women in the US is 43 μg/L 1
- ESPEN Guidelines: 20-200 μg/L 1
- British Society of Gastroenterology: <15 μg/L is highly specific for iron deficiency (specificity 0.99) 1
Clinical Interpretation of Ferritin Levels in Women
Definitive Iron Deficiency
- <15 μg/L: Highly specific for iron deficiency with a specificity of 0.99 1
- <12 μg/L: Specificity of 100% for iron deficiency in women of childbearing age 1
Probable Iron Deficiency
- <30 μg/L: Most specific indicator of iron deficiency in patients without inflammation 2
- <45 μg/L: Provides a specificity of 0.92 for iron deficiency; values below this may warrant consideration of GI investigation 1
Gray Zone
- 50-100 μg/L: May still be consistent with iron deficiency, especially in the presence of inflammation 3
- A ferritin level >50 μg/L does not automatically exclude iron deficiency, particularly in patients with coexisting inflammatory conditions 3
Important Considerations
Impact of Inflammation
Ferritin is an acute-phase reactant, meaning:
- Chronic infection, inflammation, or diseases can raise ferritin levels independent of iron status 1
- In inflammatory conditions, a higher cutoff (up to 50-100 μg/L) may be needed to diagnose iron deficiency 4
- C-reactive protein (CRP) should be checked to assess for inflammation when interpreting ferritin levels 2
Age-Related Variations
- Younger women (below 25 years) tend to have lower ferritin levels 5
- Studies have shown that 30-50% of healthy women may have no marrow iron stores, suggesting current reference ranges may be too low 6
Clinical Significance
- A serum ferritin concentration of <15 μg/L confirms iron deficiency in anemic women 1
- When ferritin is low (<30 μg/L), this indicates depleted iron stores even before anemia develops 2
- In the presence of inflammation, a ferritin level up to 100 μg/L may still be consistent with iron deficiency 3
Treatment Thresholds
- Iron supplementation: Generally recommended when ferritin is <30 μg/L 2
- Target for iron repletion: 50-100 μg/L 1
- Avoid supplementation: When ferritin is elevated (>500 μg/L) to prevent iron overload 2
Pitfalls to Avoid
Relying solely on ferritin: Always consider other iron parameters like transferrin saturation (<16% suggests iron deficiency) 2
Ignoring inflammation: Ferritin can be falsely elevated in inflammatory conditions despite iron deficiency 2
Using outdated cutoffs: Growing evidence suggests the physiologic ferritin "cutoff" should be closer to 50 ng/mL rather than traditional lower values 6
Over-supplementation: Continuing iron supplementation with normal or high ferritin levels can be harmful 2
Missing non-anemic iron deficiency: Women can have depleted iron stores (low ferritin) before developing anemia 1