Table 9.1-1. Classification of anemias based on RC, MCV, and RCDW



RC ≥100×109/L

RC <100×109/L

Microcytic (MCV ↓)


Beta thalassemia

Anemia of chronic disease (some cases)

Possible beta thalassemia

– Iron deficiency anemia

– Inherited sideroblastic anemia (some cases)

Normocytic (MCV [N])


– Very early phases of major bleeding

– Anemia of chronic disease (most cases)

– Anemia in chronic kidney disease

– Aplastic anemia

– Anemia due to bone marrow infiltration

– Anemia of endocrine disorders

–  Malnutrition

– Anemia due to acute blood loss

– Most hemolytic anemias

– Early stage of iron deficiency anemia

– Cobalamin or folate deficiency

– Mixed-type anemia (eg, combined iron and cobalamin deficiency)

– Myelodysplastic syndrome

– Sideroblastic anemias (some cases)

Macrocytic (MCV ↑)


Chronic liver disease

– Chemotherapy and certain medications

– Alcohol toxicity

– Aplastic anemia

– Hypothyroidism (some cases)

– Some autoimmune hemolytic anemias (due to reticulocytosis)

– Chronic liver disease

– Anemia after initiation of effective treatment or during regeneration after chemotherapy

– Cobalamin or folate deficiency

– Myelodysplastic syndrome

– Sideroblastic anemia (some cases)

↑, increased; ↓, decreased; MCV, mean corpuscular volume; N, normal; RC, reticulocyte count; RDW, red cell distribution width.