Which classification of anemia is characterized by macrocytic red cells and an absence of effective erythropoiesis?

The classification of anemia characterized by macrocytic red cells and an absence of effective erythropoiesis is pure red cell aplasia. This condition is primarily defined by the marked reduction or absence of erythroid progenitor cells in the bone marrow, which leads to inadequate production of red blood cells.

In pure red cell aplasia, despite the presence of other hematopoietic lineages (white blood cells and platelets), the absence of effective erythropoiesis results in a significant decrease in red blood cell production. This lack of red cell production is often reflected in the macrocytic appearance of the red cells that are eventually produced, as the body attempts to compensate for low red cell counts.

Understanding the characteristics of this anemia is crucial as it helps differentiate it from other types of anemia, such as those stemming from iron deficiency or hemolysis, where the mechanism and resulting red blood cell characteristics differ significantly.