When a person has evidence of liver disease, very high ALP levels can tell the doctor that the person’s bile ducts are somehow blocked. Often, ALP is high in persons who have cancer that has spread to the liver or the bones, and doctors can do further testing to see if this has happened. If a person with bone or liver cancer responds to treatment, ALP levels will decrease. When a person has high levels of ALP, and the doctor is not sure why, s/he may also order ALP isoenzyme tests to try to determine the cause.
ALP is generally part of a routine lab testing profile, often with a group of other tests called a liver panel. It is also usually ordered along with several other tests if a patient seems to have symptoms of a liver or bone disorder.
What does the test result mean? NOTE: This test has no single number that identifies an abnormal result.
Your lab report (see a sample report) should include
a range of numbers (reference range) that identifies what is expected for you based on
your age, sex, and the method used in that laboratory. You can find more information
about expected results at Reference Ranges
and What They Mean. Lab Tests Online strongly recommends that you discuss the meaning of your test results with your doctor.
In some forms of liver disease, such as hepatitis, ALP is usually much less elevated than AST and ALT. When the bile ducts are blocked (usually by gallstones, scars from previous gallstones or surgery, or by cancers), ALP and bilirubin may be increased much more than AST or ALT. In a few liver diseases, ALP may be the only test that is high.
In some bone diseases, such as a disorder called Paget’s disease (where bones become enlarged and deformed), or in certain cancers that spread to bone, ALP may be the only test result that is high.
Sometimes doctors don’t know why ALP is high, and they need to order other tests to determine the exact cause. In such cases, your doctor may order another enzyme, GGT, that is made by the liver in the same places as is ALP, but which is not made by bone.
Children have higher ALP levels because their bones are growing, and ALP is often very high during the growth spurt, which occurs at different ages in males and females.
Some drugs may increase ALP levels, especially some of the drugs used to treat psychiatric problems, but this is rare.
This article was last reviewed on July 30, 2007.
This page was last modified on April 8, 2009.
The review date indicates when the article was last reviewed from beginning to end to ensure that it reflects the most current science. A review may not require any modifications to the article, so the two dates may not always agree.
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