Which red blood cell morphology is typical of iron deficiency anemia?

• A. Macrocytic
• B. Microcytic hypochromic
• C. Normocytic normochromic
• D. Spherocytic

Answer: (B)

Iron deficiency anemia causes less hemoglobin to be produced in each red blood cell, so the cells become smaller and carry less hemoglobin. This yields microcytic (small) and hypochromic (pale) red blood cells, a classic pattern seen on a blood smear. In other words, the hallmark morphology is microcytosis with reduced hemoglobin content. Early on, you might see normocytic normochromic RBCs, but as iron deficiency progresses, microcytic hypochromic becomes typical. For contrast, macrocytic cells appear with B12 or folate deficiency, and spherocytes arise from membrane disorders or autoimmune hemolysis, not iron deficiency.