Is ferritin elevated in anemia or chronic disease?

Ferritin Levels in Anemia and Chronic Disease

Ferritin is typically low in iron deficiency anemia but elevated in anemia of chronic disease due to inflammatory processes. 1, 2

Ferritin Patterns in Different Types of Anemia

Iron Deficiency Anemia (IDA)

• Ferritin levels are typically low (<30 μg/L) in the absence of inflammation 2
• Represents true depletion of iron stores 1
• Transferrin saturation is also low (<16%) 1
• Often caused by chronic blood loss, reduced iron intake, or malabsorption 1

Anemia of Chronic Disease (ACD)

• Ferritin levels are elevated (>100 μg/L) despite functional iron deficiency 1
• Transferrin saturation is typically low (<16%) despite adequate or elevated ferritin 1
• Inflammation drives increased ferritin production as an acute phase reactant 1, 3
• Hepcidin levels increase during inflammation, blocking iron absorption and release from stores 3

Mixed Anemia (IDA + ACD)

• Ferritin levels typically fall between 30-100 μg/L when both conditions coexist 1, 2
• Challenging to diagnose as inflammation masks the true iron status 1
• Requires additional testing beyond standard ferritin measurement 4

Diagnostic Approach

When evaluating ferritin levels in anemia:

1. Consider inflammatory status first:

   • Check inflammatory markers (CRP, ESR, leukocytosis) 1
   • Ferritin interpretation changes significantly in the presence of inflammation

2. Interpret ferritin based on inflammation status:

   • Without inflammation: ferritin <30 μg/L indicates iron deficiency 2
   • With inflammation: ferritin <100 μg/L may still indicate iron deficiency 1, 2
   • With inflammation: ferritin >100 μg/L suggests anemia of chronic disease 1

3. Additional testing for complex cases:

   • Transferrin saturation (<16% suggests iron deficiency regardless of ferritin) 1
   • Soluble transferrin receptor (sTfR) - not affected by inflammation 4
   • sTfR-ferritin index - highly sensitive (91%) and specific (92%) for IDA in inflammatory conditions 4
   • Percent of hypochromic red blood cells (>10% suggests iron deficiency) 1

Clinical Pearls and Pitfalls

• Major pitfall: Relying solely on ferritin without considering inflammatory status can lead to missed iron deficiency diagnoses 1, 3

• Remember: Ferritin can be markedly elevated in conditions beyond anemia, including:

  • Malignancy (most common cause of very high ferritin) 5
  • Iron overload syndromes 5
  • Liver disease 6
  • Severe inflammatory conditions (adult-onset Still's disease, hemophagocytic lymphohistiocytosis) 5

• Treatment consideration: Standard oral iron therapy for iron deficiency anemia does not cause immediate ferritin elevation until hemoglobin normalizes 6

• Monitoring tip: In chronic kidney disease patients with inflammation, ferritin targets should be higher than in those without inflammation 3

By understanding these patterns, clinicians can more accurately diagnose the type of anemia present and select appropriate treatment strategies.