The hemolytic anemias.

Hemolytic anemias usually present with persistent reticulocytosis, a characteristic that differentiates them from other types of anemia. Once the presence of a hemolytic process has been documented, simple observation of red blood cell morphology will yield important etiologic information. Hemolysis may result from inherent defects in the red cell or from excessive environmental stress on normal cells. Immune mechanisms of hemolysis should be investigated early because of the frequency of their occurrence.