The Alkaline-Phosphatase (ALP) or Bone-Fraction test is used to monitor treatment for a liver or bone disorder. ALP is an enzyme found in several tissues throughout the body. The highest concentrations of ALP are present in the cells that comprise bone and liver. Elevated levels of ALP in the blood are most commonly caused by liver disease or bone disorders. This test measures the level of ALP in the blood. This test can be carried out as part of a routine liver panel or when you have symptoms of a liver or bone disorder.