A 28-year-old man of Mediterranean origin has Hb 11.5 g/dL, MCV 64 fL, RDW normal, and numerous target cells. Mentzer index is 12. Hemoglobin electrophoresis shows HbA2 of 6.0% (normal 1.5 to 3.5%). Serum ferritin is 90 ng/mL. The most likely diagnosis is:

• A Beta thalassemia minor ✓
• B Iron deficiency anemia
• C Anemia of chronic disease
• D Sideroblastic anemia

Explanation

Microcytosis with disproportionately mild anemia, a Mentzer index below 13, normal RDW, and normal ferritin point to beta thalassemia trait. The diagnostic confirmation is elevated HbA2 above 3.5%, resulting from unbalanced alpha and delta chain synthesis relative to absent or reduced beta chain production. In iron deficiency the Mentzer index exceeds 13, RDW is typically raised, and HbA2 falls. Ferritin of 90 ng/mL excludes iron deficiency and makes option B the strongest distractor to eliminate first.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.