Preferential staining of granulocytic cells by sulphonaphthyl red

Using sulphonaphythyl red (Michrome #947), granules in mature and immature granulocytic cells stained bright red. Granules were not visualized in other types of normal or leukemic blood cells. As such, sulphonaphthyl red may be useful in distinguishing normal and abnormal granulocytic cells from other types of blood and bone marrow cells.