Which of the following is NOT one of the three major classifications of anemia?

• A. Excessive blood loss
• B. Excessive RBC destruction
• C. Deficient RBC or hemoglobin production
• D. Low iron stores

Answer: (D)

Anemias are usually grouped by the mechanism that reduces red blood cell mass: loss of blood causing hemorrhagic anemia, destruction of red cells leading to hemolytic anemia, and impaired production of red blood cells or hemoglobin resulting in a hypoproliferative anemia. Low iron stores describes a specific situation—iron deficiency—that often underlies reduced production, but it is not a broad mechanism itself. It’s an etiologic detail within the decreased-production category, not one of the three major classifications by mechanism. So the statement describing low iron stores is not a major classification, while the other terms map to the three recognized mechanistic groups: blood loss, increased destruction, and deficient production.