Classification of anemias based on reticulocyte count, mean corpuscular volume, and red cell distribution width

Table 9.1-1. Classification of anemias based on RC, MCV, and RCDW
MCV	RDW	RC ≥100×109/L	RC <100×109/L
Microcytic (MCV ↓)	N	Beta thalassemia	Anemia of chronic disease (some cases)
Microcytic (MCV ↓)	↑	Possible beta thalassemia	– Iron deficiency anemia – Inherited sideroblastic anemia (some cases)
Normocytic (MCV [N])	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
Normocytic (MCV [N])	↑	– 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 ↑)	N	Chronic liver disease	– Chemotherapy and certain medications – Alcohol toxicity – Aplastic anemia – Hypothyroidism (some cases)
Macrocytic (MCV ↑)	↑	– 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.