The reasoning: size × response × compensation
Indices: MCV = Hct (%) × 10 ÷ RBC (10¹²/L) [80–100 fL]; MCH = Hb (g/dL) × 10 ÷ RBC [27–32 pg]; MCHC = Hb ÷ Hct × 100 [32–36 g/dL]; RDW reflects size variation (high in iron deficiency, normal in thalassaemia trait). WHO anaemia thresholds: Hb < 13 g/dL (men), < 12 (non‑pregnant women), < 11 (pregnancy).