The alkaline phosphatase test (ALP) is used to help detect liver disease or bone disorders.
In conditions affecting the liver, damaged liver cells release increased amounts of ALP into the blood. This test is often used to detect blocked bile ducts because ALP is especially high in the edges of cells that join to form bile ducts. If one or more of them are obstructed, for example by a tumor, then blood levels of ALP will often be high.
An ALP test may be ordered as part of routine laboratory testing, often with a group of other tests called a liver panel. It is also usually ordered along with several other tests when a person has symptoms of a liver or bone disorder.
Signs and symptoms of liver involvement may include:
Loss of appetite
Abdominal swelling and/or pain
Dark urine, light-colored stool
Some examples of the signs and symptoms suggesting a bone disorder include:
Bone and/or joint pain
Increased frequency of fractures