Which morphological classification is characteristic of megaloblastic anemia?

The characteristic morphological classification of megaloblastic anemia is macrocytic, normochromic. This classification is defined by the presence of larger than normal red blood cells (macrocytes), which occur due to impaired DNA synthesis that leads to ineffective erythropoiesis.

In megaloblastic anemia, often caused by deficiencies in vitamin B12 or folate, the maturation of red blood cells is disrupted, resulting in their enlargement. The normal hemoglobin content relative to cell size gives them a normochromic appearance. This means that while these cells are larger than typical (macrocytic), they maintain a normal level of coloration, which reflects sufficient hemoglobin.

Understanding this classification helps in diagnosing the type of anemia and directing appropriate treatments, such as supplementation of the deficient vitamin or addressing other underlying causes. The other classifications do not apply because they either describe red blood cells that are not enlarged or do not account for the typical features seen in megaloblastic anemia.