Blood
Bone-Specific Alkaline Phosphatase
Also known as: Bone ALP, BAP
CONVERT & COMPARE
µg/L
=
10
mcg/L
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10
ug/L
=
10
ng/mL
Reference ranges by source
Published adult intervals: 3, from 1 named sources, shown in µg/L.
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AGE
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About Bone-Specific Alkaline Phosphatase
An alkaline phosphatase (ALP) test measures the amount of ALP in your blood. ALP is an enzyme, a protein that speeds up certain chemical reactions in your body. ALP is found in all your body tissues, but higher amounts can be found in your liver, bile ducts, and bones. Each part of your body makes a different type of ALP. Bone-specific ALP comes from cells in your bones that build new bone tissue, so it can rise when bone-building activity is unusually high.
Abnormal levels of ALP in your blood may be a sign of a wide range of health conditions, including liver disease, bone disorders, and chronic kidney disease. The amount of ALP released into your blood can be affected by liver damage, conditions that affect bone growth, and certain gastrointestinal diseases. But an alkaline phosphatase test alone can't identify the source of ALP in your blood, so other tests are usually needed to make a diagnosis.
Your health care provider may order an alkaline phosphatase test as part of a routine checkup. Many conditions may affect ALP levels, so the test is often done with other blood tests. These other tests can include a comprehensive metabolic panel (CMP) or liver function tests, which check how well your liver is working.
Main source: MedlinePlus ↗
Useful for
Screening for or helping diagnose diseases of the liver or bones
Helping look into bone disorders linked with increased bone-building activity, such as Paget's disease of bone
Helping diagnose or monitor other health conditions that may affect ALP levels
Main source: MedlinePlus ↗
Interpretation
High alkaline phosphatase (ALP) levels may be a sign of a liver problem or a bone disorder. Liver problems and bone disorders create different types of ALP. But your ALP test results can't tell which type of ALP is high.
If your test results show high ALP levels, your provider may order other tests to help figure out what's causing the problem.
If alkaline phosphatase levels are high and the results of liver tests are normal, the problem may be a bone disorder, such as Paget's disease of bone. This disease makes your bones unusually large and weak, causing them to break more easily.
Some moderate increases in ALP can also come from conditions that don't directly involve the liver or the bones.
For general wellness information only. Talk to a clinician about your specific results.
Main source: MedlinePlus ↗
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Sources
Last updated 2026-05-02
This page presents source-specific reference data and sourced explanations. For general wellness information only. This is not medical advice. For diagnosis or treatment of any condition, talk to a qualified clinician.