Which disorder would be associated with a right shift in the RBC histogram?

Which disorder would be associated with a right shift in the RBC histogram?

• A. Pernicious anemia
• B. Iron deficiency anemia
• C. Sickle cell anemia
• D. Aplastic anemia

Answer: (A)

A RBC histogram that shifts to the right indicates macrocytosis, meaning more and larger red blood cells. This occurs when there’s impaired DNA synthesis causing the cells to mature with a larger size, as seen in megaloblastic processes. Pernicious anemia causes vitamin B12 deficiency, a classic cause of macrocytic anemia, so the histogram shows a rightward shift due to the increased size of the circulating erythrocytes. In contrast, iron deficiency anemia produces microcytosis (smaller cells, leftward shift), and the other listed conditions do not characteristically produce the macrocytosis that drives a right shift in the histogram.

A RBC histogram that shifts to the right indicates macrocytosis, meaning more and larger red blood cells. This occurs when there’s impaired DNA synthesis causing the cells to mature with a larger size, as seen in megaloblastic processes. Pernicious anemia causes vitamin B12 deficiency, a classic cause of macrocytic anemia, so the histogram shows a rightward shift due to the increased size of the circulating erythrocytes. In contrast, iron deficiency anemia produces microcytosis (smaller cells, leftward shift), and the other listed conditions do not characteristically produce the macrocytosis that drives a right shift in the histogram.