Which peripheral smear findings are typical of iron deficiency anemia?

• A. Microcytosis and hypochromia with anisocytosis and poikilocytosis; pencil or spoon nails.
• B. Macrocytosis with hypersegmented neutrophils.
• C. Normocytic, normochromic cells with normal platelets.
• D. Sideroblastic rings and ringed sideroblasts.

Answer: (A)

Iron deficiency anemia arises when iron stores are depleted, so red blood cells are produced with insufficient hemoglobin. That leads to microcytosis (smaller-than-normal red cells) and hypochromia (paler red cells). The iron shortage also causes uneven erythropoiesis, resulting in anisocytosis and poikilocytosis on the smear, meaning there’s more variation in RBC size and shape. In chronic iron deficiency, you may also see koilonychia, the characteristic pencil or spoon-shaped nails. This pattern—small, pale cells with variable sizes and shapes—is what makes iron deficiency distinct from other anemias. Macrocytosis with hypersegmented neutrophils points to B12 or folate deficiency, a normocytic picture with normal platelets isn’t typical for iron deficiency, and sideroblastic forms show ring sideroblasts rather than the microcytic, hypochromic cells described above.