leukocyte alkaline phosphatase

alkaline phosphatase /al·ka·line phos·pha·tase/ (ALP) (fos´fah-tās) an enzyme that catalyzes the cleavage of orthophosphate from orthophosphoric monoesters under alkaline conditions. Differing forms of the enzyme occur in normal and malignant tissues. The activity in serum is useful in the clinical diagnosis of many illnesses. Deficient bone enzyme activity, an autosomal recessive trait, causes hypophosphatasia.

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leukocyte alkaline phosphatase  (LAP) the isozyme of alkaline phosphatase occurring in the leukocytes, specifically in the neutrophils; LAP activity is used in the differential diagnosis of neutrophilia, being lowered in chronic myelogenous leukemia but elevated in a variety of other disorders.

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leukocyte alkaline phosphatase (LAP),

an enzyme present in lymphocytes that is elevated in various diseases such as cirrhosis and polycythemia and in certain infections. It is measured in the blood to detect these disorders and to differentiate chronic myelogenous (myelocytic) leukemia from leukemoid reactions. Normal amounts of this enzyme in a smear of fresh venous blood are 50 to 150 units. Also called neutrophil alkaline phosphatase.