Certified Neuroscience Registered Nurse (CNRN) Practice Exam

Megaloblastic anemia is primarily characterized by what type of blood cells?

1. Microcytic red blood cells

2. Megaloblastic red blood cells

3. Normocytic red blood cells

4. Hypochromic red blood cells

The correct answer is: Megaloblastic red blood cells

Megaloblastic anemia is specifically characterized by the presence of megaloblastic red blood cells, which are larger than normal red blood cells due to impaired DNA synthesis. This condition typically arises from deficiencies in vitamin B12 or folate, leading to the production of abnormally large and immature red blood cells in the bone marrow, termed megaloblasts. These megaloblastic cells are often evident in a blood smear and are a hallmark sign of the condition. In contrast, the other types of red blood cells mentioned reflect different types of anemia caused by various factors. For example, microcytic red blood cells are usually associated with iron deficiency anemia, while normocytic red blood cells are seen in situations where red cell production is normal but the overall red cell mass is decreased, such as in chronic disease. Hypochromic red blood cells indicate lower hemoglobin content and are commonly found in iron deficiency anemia. Therefore, the defining characteristic of megaloblastic anemia is indeed the presence of megaloblastic red blood cells.