The Incorrect Statement is A: Anemia of Chronic Disease is NOT Characterized by Elevated Serum Iron
Statement A is incorrect—anemia of chronic disease (ACD) is characterized by LOW serum iron, not elevated serum iron. This is a fundamental distinguishing feature of ACD pathophysiology.
Why Statement A is Wrong
In ACD, serum iron is characteristically LOW due to inflammation-driven iron sequestration within macrophages and hepatocytes 1. The pathophysiologic mechanism involves:
- Hepcidin upregulation by inflammatory cytokines, which binds to ferroportin (the iron export protein) on macrophages and enterocytes
- This causes degradation of ferroportin, trapping iron within the reticuloendothelial system
- The result is reduced transferrin saturation (<20%) and decreased iron availability for erythropoiesis, creating "functional iron deficiency" 1
The diagnostic criteria for ACD explicitly require transferrin saturation <20%, which reflects low circulating iron 1, 2.
Why the Other Statements Are Correct
Statement B: Serum Ferritin is Usually Elevated ✓
Correct. ACD diagnostic criteria specify ferritin >100 μg/L in the presence of inflammation 1, 2. Ferritin is an acute-phase reactant that rises during inflammation, even when total body iron stores may be depleted.
Statement C: Ferritin May Be Normal with Coexisting Iron Deficiency ✓
Correct. When ACD coexists with true iron deficiency, ferritin levels between 30-100 μg/L indicate a mixed picture 1. The inflammatory elevation of ferritin can mask underlying iron deficiency, making ferritin appear "normal" when it should be low.
Statement D: Associated with Elevated Hepcidin ✓
Correct. Hepcidin is the central pathophysiologic mediator of ACD 1. Inflammatory cytokines upregulate hepatic hepcidin production, which is the master regulator causing iron sequestration and reduced iron availability for erythropoiesis.
Statement E: Second Most Common Anemia Worldwide ✓
Correct. ACD is recognized as the second most common cause of anemia globally, after iron-deficiency anemia 3. It occurs in patients with chronic infections, autoimmune diseases, malignancies, chronic kidney disease, and other inflammatory conditions.
Clinical Pitfall to Avoid
The key diagnostic error is confusing low serum iron (characteristic of ACD) with elevated serum iron. The iron studies pattern in ACD shows:
- Low serum iron
- Low transferrin saturation (<20%)
- Elevated or normal ferritin (>100 μg/L with inflammation)
- Normal or reduced total iron-binding capacity
This contrasts with iron deficiency anemia, which shows low ferritin (<30 μg/L without inflammation) and elevated total iron-binding capacity.