Identification of neutrophils with an oxazine dye

Used in an alkaline-buffered solution on fixed smears of bone marrow or peripheral blood, the oxazine dye CI basic blue 141 preferentially stained neutrophil granules a bright crimson red. In neutrophils, these granules were numerous, whereas in bands, only a few granules were seen. In other types of blood or bone marrow cells, crimson red granules of the type described were not found to an appreciable degree. Used as a tinctorial stain, this dye may be useful in the study of disorders of neutrophil function and neutrophil physiologic characteristics, as well as in the identification of neutrophils and their distinction from other types of cells.