What is the difference between anemia of chronic disease and iron deficiency anemia?

From the Guidelines

Anemia of chronic disease (ACD) and iron deficiency anemia (IDA) can be differentiated based on their underlying mechanisms, laboratory findings, and treatment approaches, with ACD typically having elevated ferritin levels (>100 ng/mL) and IDA having low ferritin levels (<30 ng/mL) 1. The primary distinction between ACD and IDA lies in their pathophysiology, with ACD resulting from chronic inflammation, infections, or malignancies that disrupt normal iron metabolism, and IDA resulting from inadequate iron intake, absorption, or excessive blood loss.

• Key laboratory findings for ACD include low serum iron, low transferrin saturation, elevated or normal ferritin levels, and normal or reduced total iron binding capacity (TIBC) 1.
• In contrast, IDA is characterized by low serum iron, low transferrin saturation, low ferritin levels, and increased TIBC.
• Soluble transferrin receptor levels can also help differentiate between the two conditions, with elevated levels in IDA and normal levels in isolated ACD. Treatment approaches for ACD and IDA differ significantly, with IDA requiring iron supplementation (oral ferrous sulfate 325mg three times daily or IV iron if oral therapy fails) 1, and ACD management focusing on treating the underlying condition, with iron supplementation potentially harmful unless concurrent true iron deficiency exists.
• The reticulocyte hemoglobin content and hepcidin levels can help differentiate between ACD and IDA in challenging cases, with hepcidin levels typically elevated in ACD due to increased inflammation 1. In clinical practice, it is essential to accurately diagnose and differentiate between ACD and IDA to provide appropriate treatment and improve patient outcomes, as incorrect diagnosis and treatment can lead to adverse consequences, such as worsening of anemia, increased morbidity, and mortality 1.

From the Research

Difference between Anemia of Chronic Disease and Iron Deficiency Anemia

• Anemia of chronic disease (ACD) and iron deficiency anemia (IDA) are two distinct types of anemia that can present with similar clinical and laboratory features, making differential diagnosis challenging 2.
• ACD is characterized by low serum iron and increased reticuloendothelial stores of iron, and is mediated by inflammatory cytokines, whereas IDA is caused by low iron stores 3.
• The treatment for ACD and IDA differs, with IDA requiring iron therapy and ACD often requiring treatment of the underlying disease, and potentially erythropoietic agents and iron supplementation if necessary 4, 3.

Diagnostic Approaches

• Traditional diagnostic approaches involve analysis of multiple biochemical and haematological parameters, including bone marrow examination, which can be invasive and cumbersome 5.
• Newer erythrocyte parameters, such as reticulocyte hemoglobin (Ret Hb) and percentage microcytic RBCs (%Micro R), have been studied as potential diagnostic markers to differentiate between IDA and ACD 5.
• Ret Hb has been shown to be a reliable indicator of IDA, with a high sensitivity and specificity, and can be used as a marker to differentiate between IDA and ACD 5.
• Hepcidin, the master regulator of iron homeostasis, has also been investigated as a potential diagnostic marker, and has been shown to be useful in identifying iron deficiency in patients with ACD 6, 3.

Diagnostic Pathways

• A simplified diagnostic pathway using hepcidin and reticulocyte haemoglobin equivalent (RetHe) has been proposed, which can help to differentiate between IDA and ACD, and exclude IDA in patients with mixed aetiology 6.
• This pathway has the potential to reduce diagnostic turnaround time and allow for appropriate treatment of patients with true iron deficiency 6.