Which erythrocyte inclusion is detectable with supravital stain but not on a Wright's-stained blood smear?

Heinz bodies are aggregates of denatured hemoglobin that form within red blood cells as a result of oxidative stress, commonly associated with conditions like G6PD deficiency or hemolytic anemia. These inclusions are typically not visible on a Wright's-stained blood smear because the stain does not effectively reveal them. However, when a supravital stain, such as New Methylene Blue, is applied to a fresh blood sample, it can highlight the presence of Heinz bodies. This occurs because the supravital stain acts on live cells, allowing the visualization of these intracellular structures that may be lost or obscured by the fixation and staining processes of the Wright's stain.

In contrast, other inclusions such as basophilic stippling, Howell-Jolly bodies, and siderotic granules can be identified using Wright's stain, as they are more stable structures retained even in the fixed state of the cells. This distinction helps practitioners in diagnosing and understanding various hematological conditions by providing insights into the specific types of red blood cell abnormalities present.