Two cytochemical stains are performed in the hematopathology laboratory. These studies can be performed on unstained peripheral blood or bone marrow aspirate smears, anticoagulated peripheral blood or bone marrow aspirate material.
The myeloperoxidase stain is positive in cells of the granulocyte series. Occasionally, cells in the monocyte series will have a few positive granules, but lymphoid cells are negative. Myeloperoxidase activity increases as myeloid cells mature, so very immature myeloid blasts will have absent to weak staining.
Non-specific Esterase (NSE)
The non-specific esterase stain used in our laboratory is for a-naphthyl butyrate esterase. This stain is positive in cells from the monocyte and megakaryocyte series. Lymphocytes may stain focally and occasionally myeloid cells will stain very weakly. This stain is most commonly used to confirm a diagnosis of acute myelogenous leukemias with monocytic differentiation (FAB types M4 and M5).
Last updated: 6/15/08