neutrophil alkaline phosphatase

Last reviewed 01/2018

Leukocyte alkalline phosphatase (LAP) (neutrophil alkaline phosphatase)

• is an enzyme present in normal neutrophils, but absent (or present at very low concentrations) in malignant neutrophils (e.g. in chronic myeloid leukaemia)
  • means that if the neutrophil count is raised, and the LAP is strongly positive in these cells, then it suggests the increase in neutrophil count is from a non malignant cause

Reference range

• 20-180 per 100 score neutrophils

Note that reference ranges may vary between laboratories