What are normal serum ferritin levels?

Normal Serum Ferritin Levels

Normal serum ferritin levels are approximately 135 μg/L for men, 43 μg/L for women, and 30 μg/L for children aged 6-24 months, with these values representing average concentrations rather than strict diagnostic cutoffs. 1

Normal Range by Population Group

Adults

• Men:

  • Average: 135 μg/L 1
  • Normal range: 21-447 μg/L (95% confidence interval) 2
  • Upper limit of normal: 193 μg/L 3

• Women:

  • Average: 43 μg/L 1
  • Normal range: 26-279 μg/L (95% confidence interval) for non-menstruating women 2
  • Upper limit of normal: 146 μg/L 3
  • Note: Levels tend to be lower in menstruating women, especially those with menstruation lasting ≥4 days 2

Children

• Children aged 6-24 months: Approximately 30 μg/L 1
• Adolescents: Should remain above 30 μg/L to prevent iron deficiency 4

Clinical Interpretation of Ferritin Levels

Low Ferritin

• <15 μg/L: Indicates absolute iron deficiency 5
• <20 μg/L: Consistent with uncomplicated iron deficiency anemia 2
• <30 μg/L: Indicates iron deficiency in the absence of inflammation 1

Normal to High Ferritin

• 30-50 μg/L: Provides optimal iron stores while avoiding risks of deficiency or excess 4
• >100 μg/L with transferrin saturation <16%: Suggests anemia of chronic disease in the presence of inflammation 1
• 30-100 μg/L with transferrin saturation <16%: Suggests combined iron deficiency and anemia of chronic disease in the presence of inflammation 1

Important Clinical Considerations

Ferritin as an Acute Phase Reactant

• Ferritin levels can be elevated in inflammatory conditions, masking underlying iron deficiency 1
• In the presence of inflammation, a ferritin level up to 100 μg/L may still be consistent with iron deficiency 1, 6

Diagnostic Approach

• Always measure ferritin alongside other iron parameters:
  • Transferrin saturation (TS)
  • Inflammatory markers (CRP, ESR) 1
• A transferrin saturation <16% with ferritin >100 μg/L suggests anemia of chronic disease 1
• A transferrin saturation >45% with elevated ferritin may indicate iron overload 1, 4

Conditions Associated with Markedly Elevated Ferritin

• Malignancy
• Iron overload syndromes
• Inflammatory conditions (including rheumatologic diseases)
• Infections
• Liver disease 7

Clinical Algorithm for Interpreting Ferritin Levels

1. Measure serum ferritin along with transferrin saturation and inflammatory markers
2. Interpret based on inflammatory status:
   • Without inflammation:
     • <30 μg/L: Iron deficiency
     • 30-200 μg/L (men) or 30-150 μg/L (women): Normal

     • 200 μg/L (men) or >150 μg/L (women): Consider iron overload

   • With inflammation:
     • <100 μg/L: Likely iron deficiency despite inflammation
     • 100-300 μg/L: Possible iron deficiency, evaluate transferrin saturation

     • 300 μg/L: Likely adequate iron stores, elevated due to inflammation

Remember that ferritin is the most specific indicator of depleted iron stores when used with other tests to assess iron status, with a direct relationship to the amount of iron stored in the body (1 μg/L of serum ferritin equals approximately 10 mg of stored iron) 1.