Leukocyte alkaline phosphatase stain of neutrophils. Blood film. Composite of (A) normal neutrophils. Image shows the characteristic range of reaction strength of normal neutrophils from zero to about a score of two out of four. Characteristically the score of each of 100 segmented and band neutrophils is summed to give a total score that might average about 80. (B) Segmented and band neutrophils in chronic myelogenous leukemia in which the neutrophilic cells are very weakly positive or negative. In this image the band and segmented neutrophils score zero out of four and the total score would be very low, characteristic of chronic myelogenous leukemia. The availability of measurements of the Ph chromosome and BCR-ABL in CML and other specific markers in diseases in which the leukocyte alkaline phosphatase is altered has made this measurement obsolete in most laboratories. (C) Reactive neutrophilia in which the alkaline phosphatase reaction is strongly positive. These neutrophils are a score of four out of four. In such a sample, the total score of 100 neutrophils counted would be far above the normal range.