From the Guidelines
In anemia of chronic disease, the iron study pattern typically shows low serum iron, low total iron binding capacity (TIBC), low transferrin saturation, and normal to elevated ferritin levels, as supported by the most recent guideline from 2023 1. This pattern reflects the body's inflammatory response to chronic conditions, where iron becomes sequestered in macrophages and the liver, making it unavailable for erythropoiesis despite adequate iron stores. The key distinguishing feature from iron deficiency anemia is the ferritin level, which is elevated in anemia of chronic disease due to its role as an acute phase reactant during inflammation, as noted in the 2017 ESPEN guideline 1. Some key points to consider in the diagnosis and management of anemia of chronic disease include:
- The diagnostic criteria for anemia of chronic disease are a serum ferritin >100 mg/L and transferrin saturation <20% in the presence of biochemical or clinical evidence of inflammation, as stated in the 2023 ESPEN guideline 1.
- If the serum ferritin level is between 30 and 100 mg/L, a combination of true iron deficiency and anemia of chronic disease is likely, as noted in the 2017 ESPEN guideline 1.
- Treatment should focus on addressing the underlying chronic condition rather than iron supplementation, as iron stores are adequate but functionally unavailable, as recommended in the 2015 European consensus on the diagnosis and management of iron deficiency and anaemia in inflammatory bowel diseases 1.
- However, iron supplementation may be necessary in some cases, and intravenous iron is more effective and better tolerated than oral iron in patients with clinically active IBD, as concluded in the 2023 ESPEN guideline 1. The underlying chronic conditions causing this pattern may include infections, autoimmune disorders, chronic kidney disease, or malignancies. It is essential to consider the patient's individual circumstances and the underlying chronic condition when making treatment decisions, as emphasized in the 2017 ESPEN guideline 1.
From the Research
Iron Study Pattern for Anemia of Chronic Disease
The iron study pattern for anemia of chronic disease is characterized by:
- Low serum iron 2
- Decreased serum transferrin 2
- Decreased transferrin saturation 2
- Increased serum ferritin 2
- Increased reticuloendothelial iron stores 2
- Increased erythrocyte-free protoporphyrin 2
- Reduced iron absorption 2, 3
Diagnostic Approaches
To differentiate between anemia of chronic disease and iron deficiency anemia, the following diagnostic approaches can be used:
- Soluble transferrin receptor (sTfR) 3
- sTfR/log ferritin index (sTfR Index) 3
- Ferritin levels 4, 5
- Transferrin saturation 6
Key Findings
- Disordered iron metabolism is a characteristic feature of anemia of chronic disease, but it may not be central to its pathogenesis 2
- Impaired erythropoietin production and responsiveness of erythroid progenitor cells to this hormone are important abnormalities contributing to the anemia of chronic disease 2
- Recombinant erythropoietin therapy can correct the anemia of chronic disease, but it cannot correct the anemia due to iron deficiency 2