Heinz-body anemia: "bite cell" variant--a light and electron microscopic study.

Light and scanning electron microscopic studies of blood from five patients with drug-induced oxidant hemolysis are presented. None of the patients had a previous history of hemolytic disease and laboratory studies indicated no evidence of either glucose-6-phosphate dehydrogenase (G6PD) deficiency or unstable hemoglobinopathy. Although the red cell deformities in our patients overlapped to some extent with those reported in patients with microangiopathic hemolytic anemia (MAHA) and in patients with G6PD deficiency undergoing oxidant hemolysis, striking differences were also observed. Cell fragments, commonly found in patients with MAHA, and eccentrocytes, frequently found in patients with G6PD deficiency undergoing oxidant hemolysis, were seldom found in blood samples from the five patients in this study. Bite cells were extremely common in our patients. They are rare in patients with either of the above disorders. An awareness of the morphologic abnormalities detailed in this report may help characterize the nature of a hemolytic process so that appropriate therapy can be initiated.