A laboratory test that measures the amount of the enzyme alkaline phosphatase in white blood cells.
This test is not often used today, because of the advent of more advanced tests.
The LAP test was used as a critical indicator of chronic myeloid leukemia (CML).
The LAP score is determined by counting the amount of staining that reveals the enzyme, in 100 white blood cells.
The leukocyte alkaline phosphatase (LAP) score, which refers to the amount of alkaline phosphatase per neutrophil, will increase. In a severe infection, and toxic granulation.