A myeloperoxidase stain is performed on peripheral blood cells of a patient with acute leukemia and 85% blasts; the patient has an occasional mature neutrophil. When the stained slide is evaluated, the blasts are all negative but the mature neutrophils are strongly positive. What is the significance of this finding?

Question

Quizplus · Accepted Answer

The myeloperoxidase stain is a cytochemical test used to differentiate types of leukemia by staining myeloid cells. The fact that the mature neutrophils are strongly positive confirms that the stain worked properly, acting as an internal positive control. This indicates that the procedure was performed correctly, and the negative result in the blasts is meaningful, suggesting they are likely not of myeloid origin.

A Myeloperoxidase Stain Is Performed on Peripheral Blood Cells of a Patient