What are the normal levels of ferritin (iron storage protein)?

Normal Ferritin Levels

Normal serum ferritin levels are 30-100 μg/L in patients without inflammation, with lower values (<30 μg/L) indicating iron deficiency and higher values potentially reflecting inflammation rather than adequate iron stores. 1

Normal Reference Ranges

The normal reference ranges for serum ferritin vary by sex and inflammatory status:

• Without inflammation:

  • Men: 30-300 μg/L (mean ~93 μg/L) 1, 2
  • Women: 30-200 μg/L (mean ~34 μg/L) 1, 2
  • Lower limit indicating iron deficiency: <30 μg/L 1

• With inflammation/chronic disease:

  • Iron deficiency should be considered at higher ferritin levels (up to 100 μg/L) 1
  • Ferritin between 30-100 μg/L with inflammation likely indicates combined iron deficiency and anemia of chronic disease 1
  • Ferritin >100 μg/L with transferrin saturation <16% suggests anemia of chronic disease 1

Interpretation of Ferritin Levels

Ferritin interpretation requires consideration of inflammatory status:

• <30 μg/L: Absolute iron deficiency in non-inflammatory conditions 3, 1
• 30-100 μg/L:
  • In healthy individuals: Likely adequate iron stores
  • In inflammatory conditions: May still represent iron deficiency 1, 4
• >100 μg/L with low transferrin saturation (<20%): Functional iron deficiency or anemia of inflammation 1
• >300 μg/L: Usually indicates adequate or excess iron stores, inflammation, or other conditions 1

Important Clinical Considerations

• Inflammatory impact: Ferritin is an acute phase reactant that increases with inflammation independent of iron stores 1
• Transferrin saturation: Should be measured alongside ferritin for better assessment of iron status; TSAT <20% suggests inadequate iron availability for erythropoiesis 3, 1
• Additional markers: Reticulocyte hemoglobin content (<30 pg) and percentage of hypochromic RBCs (>5%) can help identify functional iron deficiency 3, 1

Common Pitfalls in Ferritin Interpretation

• Relying solely on ferritin: Using ferritin alone without considering inflammatory status can miss iron deficiency 1, 4
• Using outdated cutoffs: The traditional cutoff of <15 μg/L for iron deficiency has inadequate sensitivity (59%) compared to <45 μg/L (85% sensitivity) 3
• Overlooking inflammation: Patients with chronic inflammatory conditions, cancer, or infection may have falsely elevated ferritin despite iron deficiency 1, 5
• Extreme elevations: Markedly elevated ferritin (>1000 μg/L) is most commonly associated with malignancy, iron overload syndromes, and severe inflammatory conditions rather than adequate iron stores 5

Target Ferritin Levels After Treatment

• Aim for ferritin levels of at least 50-100 μg/L to fully replenish iron stores 1
• Monitor ferritin 4-8 weeks after initiating treatment to assess response 1
• Continue monitoring every 6-12 months after successful treatment if risk factors persist 1

Understanding these reference ranges and their clinical context is essential for proper diagnosis and management of iron-related disorders.