What are the guidelines for diagnosing and treating anemia according to the American Society of Hematology (ASH)?

American Society of Hematology Guidelines for Diagnosing and Treating Anemia

According to the American Society of Hematology guidelines, anemia is diagnosed when hemoglobin levels fall below 135 g/L in adult males and 120 g/L in adult females, requiring a systematic evaluation of potential causes and appropriate treatment based on etiology. 1, 2

Diagnostic Approach

Initial Laboratory Evaluation

• Complete blood count (CBC) with red cell indices to classify anemia as microcytic, normocytic, or macrocytic 1, 2
• Reticulocyte count to assess bone marrow response to anemia 2, 3
• Iron studies including serum ferritin and transferrin saturation to evaluate iron status 1, 2
• Vitamin B12 and folate levels to rule out deficiencies 2, 4
• Kidney function tests to evaluate for renal disease as a potential cause 1

Classification of Anemia Based on Red Cell Indices

• Microcytic anemia (MCV < 80 fL): Consider iron deficiency, thalassemia, anemia of chronic disease, lead poisoning 1, 3
• Normocytic anemia (MCV 80-100 fL): Consider anemia of chronic disease, renal failure, endocrine disorders 1, 4
• Macrocytic anemia (MCV > 100 fL): Consider vitamin B12/folate deficiency, hypothyroidism, myelodysplasia 1, 3

Further Diagnostic Testing Based on Initial Classification

• For microcytic anemia: Iron profile workup (ferritin < 100 μg/L, transferrin saturation < 20% indicates iron deficiency) 1, 5
• For normocytic anemia: Evaluate creatinine, inflammatory markers (CRP) 1, 6
• For macrocytic anemia: TSH, vitamin B12, and folate levels 1, 4

Additional Testing When Indicated

• Hemolysis workup including direct Coombs test, lactate dehydrogenase, and peripheral blood smear if hemolysis is suspected 2, 7
• Bone marrow examination in cases of unexplained cytopenias or suspected myelodysplasia 1, 4
• Gastrointestinal evaluation (endoscopy, colonoscopy) in patients with iron deficiency anemia, particularly in men and postmenopausal women 1, 2

Treatment Approach

Iron Deficiency Anemia

• Oral iron supplementation as first-line therapy 8
• Intravenous iron for patients with intolerance to oral iron, chronic kidney disease with poor response to oral iron, or inflammatory bowel disease 8
• Identify and treat the underlying cause of iron deficiency 2

Anemia of Chronic Disease

• Treatment of the underlying condition is the primary management strategy 6
• Iron supplementation if concomitant iron deficiency is present 6
• Erythropoiesis-stimulating agents (ESAs) may be considered in severe or symptomatic anemia, particularly in chronic kidney disease 6, 8

Chemotherapy-Induced Anemia

• ESAs can be considered for patients with chemotherapy-associated anemia when hemoglobin decreases to less than 10 g/dL 1
• Carefully weigh the risks of thromboembolism in patients for whom ESAs are prescribed 1
• Red blood cell transfusion is an option depending on the severity of anemia or clinical circumstances 1

Red Blood Cell Transfusion

• Consider for severe, symptomatic anemia or hemodynamic instability 1, 2
• Decision should not be made strictly based on whether hemoglobin has reached a certain threshold 1
• Assessment should include individual patient characteristics, severity of anemia, presence and severity of comorbidities 1

Special Considerations

Monitoring

• Regular monitoring of hemoglobin levels, at least every three months in patients with chronic kidney disease 1, 8
• More frequent monitoring may be indicated in patients with diabetes due to higher prevalence of anemia 1

Population-Specific Considerations

• Standard definitions of anemia may not apply to certain populations, including pregnant or menstruating women, those living at high altitude, smokers, elderly individuals (≥70 years), non-Caucasian races, and those with chronic lung disease or hemoglobinopathy 1

Common Pitfalls

• Ferritin is an acute phase reactant and may be elevated in inflammatory states despite iron deficiency 6
• Failure to investigate the underlying cause of iron deficiency anemia, particularly in men and postmenopausal women 2
• Overreliance on a single parameter for diagnosis rather than considering the complete clinical and laboratory picture 3, 9