<prompt> Which one of the following laboratory tests differentiates leukemoid reaction from chronic myeloid leukemia?LAP leukocyte alkaline phosphataseLCA leukocyte common antigenMPO myelo-peroxidaseTRAP tarate resistant alkaline phosphatase  <response>: Leucocyte alkaline phosphate score in the cytoplasm of mature neutrophils in leukamoid reaction is characteristically high ia very useful to distinguish it from CML. Leukaemoid reaction is defined as reactive excessive leucocytosis in response to infections,intoxication ,malignant disease , in severe hemmorhage hemolysis.So mature neutrophils will be more resulting in elevated LAP.But in CML,mature neutrophils will be reduced resulting in low LAP score. Reference :Harsh mohan textbook of pathology sixth edition pg no 353. 