A 28-year-old woman presents with pallor, fatigue, and exertional dyspnoea. Blood tests show: Hb: 7 g/dL MCV: 72 fL Serum ferritin: Low Serum iron: Low TIBC: High What is the most likely cause of her anaemia? A) Iron deficiency anaemia B) Anaemia of chronic disease C) Thalassaemia D) Lead poisoning E) Sideroblastic anaemia Correct Answer: A) Iron deficiency anaemia Explanation: Iron deficiency anaemia is the most common microcytic anaemia, showing: Low MCV (microcytic anaemia) Low serum iron & ferritin (depleted iron stores) High TIBC (compensatory increase in transferrin) B) Anaemia of chronic disease → Incorrect. Shows low iron but normal/high ferritin. C) Thalassaemia → Incorrect. Microcytic anaemia with normal iron and high RBC count. D) Lead poisoning → Incorrect. Associated with basophilic stippling. E) Sideroblastic anaemia → Incorrect. Shows ringed sideroblasts on bone marrow biopsy. Key Tips for PLAB 1: ✅ Microcytic anaemia + low ferritin = Iron deficiency. ✅ Common causes: GI bleeding, menorrhagia, pregnancy. ✅ Treatment: Oral iron (ferrous sulfate).
