MPO stains primary granules. Sudan Black B stains lipid in grans and monos. CAE only grans. NSE monos, inhibited by NaF. PAS is lymphoid and some myeloid blasts. LAP score = Bands and PMNs are scored on the intensity of cytoplasmic staining from 0-4+ until 100 cells are counted. LOW is CML, PNH. HIGH in leukemoid reaction, pregnancy.