Anemia Diagnosis and Management

Diagnostic Approach

• For patients with macrocytic anemia (MCV >100 fL), evaluate TSH, folate, and vitamin B12 levels, as recommended by the American Society of Hematology 1
• Diagnose iron deficiency anemia by ferritin <100 μg/L and TSAT <20% in patients with chronic blood loss or poor iron absorption 1
• Identify anemia of inflammation/chronic disease by normal/high ferritin with low TSAT, associated with inflammatory conditions, infections, and malignancy 1

Treatment Approach

• Recommend B12 supplementation for documented deficiency, as suggested by the American College of Physicians 1
• Recommend folate supplementation for documented deficiency, as suggested by the American College of Physicians 1
• Consider iron deficiency treatment with iron supplementation regardless of hemoglobin level, as recommended by the European Crohn’s and Colitis Organisation and European consensus statements 2, 3
• For iron deficiency (ferritin <800 ng/mL and transferrin saturation <20%): IV iron has superior efficacy and should be considered as first-line, while oral iron is less effective but more commonly used, according to the European Society of Medical Oncology 4, 3

Diagnostic Testing

• Consider a bone marrow examination when diagnosis remains unclear despite initial workup 1
• Evaluate iron status with serum ferritin and transferrin saturation 2, 3
• Use the following table to guide iron deficiency treatment:

Transfusion Guidelines

• Adopt a restrictive blood transfusion strategy, aiming for a hemoglobin threshold of 7-8 g/dL in most patients, as supported by the American College of Physicians, American Society of Anesthesiologists, and American College of Critical Care Medicine 5, 6, 7, 8
• Transfuse one unit at a time in non-hemorrhaging patients, and complete transfusion within 4 hours of removing blood from storage, according to the American College of Critical Care Medicine and the American Society of Anesthesiologists 9, 8
• Monitor vital signs before, during, and after transfusion, and reassess clinical status and hemoglobin after each unit, as recommended by the American College of Critical Care Medicine and the American Society of Anesthesiologists 9, 8
• Consider blood transfusion in specific patient populations, such as:
• Use erythropoiesis-stimulating agents (ESAs) under REMS guidelines with informed consent, as recommended by the American Society of Clinical Oncology 12

Complications and Risks

• Blood transfusion carries significant risks, including increased nosocomial infections, longer ICU and hospital stays, venous thromboembolism, arterial thromboembolism, and mortality, according to the American Journal of Hematology and the American College of Critical Care Medicine 7, 8
• Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are potential complications, highlighting the need for careful patient selection and monitoring, as reported by the American Journal of Hematology and the American College of Critical Care Medicine 7, 8

Special Considerations

• In life-threatening emergencies, provide blood quickly, with O-negative blood reserved primarily for women of childbearing potential with unknown blood type, and males and postmenopausal women can safely receive O-positive blood in emergencies, as recommended by the American College of Emergency Physicians and the American Red Cross 13
• Crossmatch PRBCs to confirm compatibility with ABO and other antibodies, as recommended by the American Association of Blood Banks and the American College of Pathologists 3
• Patients with severe symptoms regardless of exact hemoglobin level, such as hemodynamic instability, significant tissue hypoxia, severe dyspnea at rest, or chest pain, may require blood transfusion, as recommended by the American College of Physicians and European consensus statements 5