A 28-year-old woman presents with fatigue and pallor. CBC shows Hb 7.2 g/dL, MCV 62 fL, MCH 19 pg, RBC 5.8 million/μL. Peripheral smear shows target cells and microcytes. Serum ferritin is 68 μg/L (normal 15–150). Hb electrophoresis shows HbA2 5.8%, HbF 3.2%, HbA 91%. What is the MOST likely diagnosis?
- A Iron deficiency anaemia
- B Beta thalassaemia trait (beta thalassaemia minor) ✓
- C Alpha thalassaemia trait (alpha thalassaemia minor)
- D Haemoglobin E disease
Correct answer: B. Beta thalassaemia trait (beta thalassaemia minor)
Explanation
Beta thalassaemia trait (minor) is characterised by: mild microcytic anaemia with a disproportionately high RBC count (>5 million/μL), target cells, normal or elevated serum ferritin (no iron deficiency), and — most diagnostically — elevated HbA2 (>3.5%, here 5.8%) on HPLC/electrophoresis. Iron deficiency would have low ferritin and normal HbA2. Alpha thalassaemia trait has normal HbA2. HbE disease shows HbE band on electrophoresis and HbA2 within normal range.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.