Anemia Classification and Treatment

Introduction to Anemia

The National Comprehensive Cancer Network recommends classifying anemia using two complementary approaches: morphologic (based on mean corpuscular volume) and kinetic (based on reticulocyte response) 1

The initial classification of anemia uses mean corpuscular volume from the complete blood count, with microcytic anemia (MCV < 80 fL) being the most common cause globally, primarily due to iron deficiency anemia 1, 2
Iron deficiency anemia is diagnosed through serum ferritin levels, with a cutoff of < 30 ng/mL being diagnostic in the absence of inflammation 1, 3, 7
Vitamin B12 and folate deficiencies are diagnosed through serum levels, with methylmalonic acid having greater sensitivity than serum B12 alone when B12 deficiency is suspected but levels are equivocal 1, 5, 7

Microcytic anemia can be caused by iron deficiency, thalassemia, anemia of chronic disease, sideroblastic anemia, and lead poisoning 1, 3
Normocytic anemia can be caused by acute hemorrhage, hemolysis, anemia of chronic inflammation, renal insufficiency, and bone marrow failure 1, 3, 4
Macrocytic anemia can be caused by vitamin B12 deficiency, folate deficiency, myelodysplastic syndrome, medication-induced, hypothyroidism, and alcoholism 1, 3, 5

The American Society of Clinical Oncology recommends treating iron deficiency anemia with oral iron supplementation as the first-line treatment for mild-moderate anemia 7, 2
The National Comprehensive Cancer Network recommends treating vitamin B12/folate deficiency with supplementation and addressing the underlying cause 1, 5, 7
The European Society for Medical Oncology recommends treating anemia of chronic disease by addressing the underlying inflammatory condition as primary therapy 2, 3

The National Comprehensive Cancer Network recommends that transfusion decisions should not be based solely on hemoglobin thresholds but on individual patient characteristics, symptom severity, and comorbidities 1, 6, 8
The American College of Physicians recommends a restrictive transfusion strategy (hemoglobin 7-9 g/dL) for hemodynamically stable chronic anemia without acute coronary syndrome 8