<prompt> Non-specific esterase is positive in all the categories of Acute Myeloid Leukemia, EXCEPT:M3M4M5M6  <response>: Non specific esterase is negative in M3 type of Acute myeloid leukemia AML. Alpha naphthyl acetate esterase ANAE, Alpha naphthyl butyrate esterase ANBE and Alpha naphthyl AS esterase NASA are the non specific esterase reactions that are positive in M4 acute myelomonocytic leukemia and M5 acute monocyticmonoblastic leukemia type of AML. Their presence is variable in M6 acute erythroid leukemia. Ref: Wintrobes Clinical Hematology, 10th Ed, Page 2221; Textbook of pathology, B N Datta, 2nd Edition, Page 1118 1119. 