Anaemia Algorithm — by MCV

MICROCYTIC (MCV < 80) — TICS • Thalassaemia (common in Pakistan) — target cells, normal/↑ RBC, ↑ HbA2 • Iron deficiency — ↓ ferritin, ↓ Tsat, ↑ TIBC, microcytic hypochromic • Chronic disease (some) — ↓ TIBC, ↑ ferritin • Sideroblastic — ringed sideroblasts on BM, ↑ ferritin, ↑ Tsat NORMOCYTIC (MCV 80–100): • Acute blood loss • Anaemia of chronic disease • Aplastic anaemia (pancytopenia) • Haemolytic anaemia (↑ retics, ↑ LDH, ↓ haptoglobin) • Renal failure (↓ EPO) MACROCYTIC (MCV > 100): • Megaloblastic — B12, folate deficiency (hypersegmented neutrophils) • Non-megaloblastic — alcohol, hypothyroidism, liver disease, drugs (MTX, hydroxyurea) KEY POINTS: • Reticulocyte count separates production failure from destruction/loss • Iron studies first if microcytic • B12/folate first if macrocytic with hypersegmented neutrophils