Sample: Several fresh blood or bone marrow smears. If it is necessary, collect the sample in any heparin anticoagulant (do not use EDTA anticoagulated samples!) and send it without delay to the lab.
Schedule: Two days
Range: 40 - 130
Remarks: Neutrophil Alkaline Phosphatase (Leucocyte Alkaline Phosphatase, LAP) score is useful in the differential diagnosis of Chronic Myelocytic Leukemia (CML) vs leukemoid reaction; also is useful for the investigation of polycythemia vera, myelofibrosis with myeloid metaplasia, and paroxysmal nocturnal hemoglobinuria. Pregnancy and infection diseases are associated with increased LAP scores. The differential smear must have an adequate amount of mature neutrophilic granulocytes to perform the LAP score test.