Which hematologic finding is classic for iron deficiency anemia?

Which hematologic finding is classic for iron deficiency anemia?

• A. Macrocytic red blood cells
• B. Normocytic red blood cells
• C. Microcytic, hypochromic red blood cells
• D. Sideroblastic red blood cells

Answer: (C)

Iron is required for making hemoglobin, so when iron is deficient, less hemoglobin is produced in each red blood cell. That leads to smaller cells (microcytosis) and cells with less color (hypochromia), producing the classic microcytic, hypochromic red blood cells of iron deficiency anemia. This pattern is what you’d expect as the body runs out of iron to build hemoglobin. Macrocytic red cells would point toward vitamin B12 or folate deficiency, not iron shortage. Normocytic cells can appear early in iron deficiency or in other anemias, so they’re not the hallmark. Sideroblastic cells reflect a different problem—impaired heme synthesis with iron trapped in mitochondria (ring sideroblasts)—not the iron-deficiency pattern.

Iron is required for making hemoglobin, so when iron is deficient, less hemoglobin is produced in each red blood cell. That leads to smaller cells (microcytosis) and cells with less color (hypochromia), producing the classic microcytic, hypochromic red blood cells of iron deficiency anemia. This pattern is what you’d expect as the body runs out of iron to build hemoglobin.

Macrocytic red cells would point toward vitamin B12 or folate deficiency, not iron shortage. Normocytic cells can appear early in iron deficiency or in other anemias, so they’re not the hallmark. Sideroblastic cells reflect a different problem—impaired heme synthesis with iron trapped in mitochondria (ring sideroblasts)—not the iron-deficiency pattern.