Cytochemical stains on blood and bone marrow smears are helpful in the distinction of AML from ALL , and in subclassification of AML . The combination of a myeloperoxidase or Sudan black stain and a nonspecific esterase stain will provide the desired information in most cases . The myeloperoxidase or Sudan black reactions are most useful in establishing the identity of AML and distinguishing it from ALL . The nonspecific esterase stain is used to identify a monocytic component in AMLs and to distinguish a poorly differentiated monoblastic leukemia from ALL .