Alkaline Phosphatase (ALP) Test
The Alkaline Phosphatase (ALP) test measures the amount of this enzyme in your blood to help evaluate liver and bone health.
{"ALP is an enzyme mainly found in your liver and bones","High ALP levels may indicate liver problems or bone disorders","The test requires a simple blood draw, usually as part of a liver function panel","Results are compared to normal ranges that vary by age and gender","Your doctor will interpret results based on your overall health and other test results"}
Key facts at a glance
- LOINC
- 13874-3
- Short code
- ALP
- Synonyms
- ALP Liver 1 SerPl-cCnc
- Category
- chemistry
- Sample
- serum
- Container
- Serum Separator Tube (SST/gold top) or plain red top tube
- Units
- not specified
- Ref low
- 40
- Ref high
- 129
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Spectrophotometry (Colorimetric p-Nitrophenyl Phosphate Substrate)
- CPT
- 84075
- SNOMED
- 271435004
- Specimen volume
- 0.5-1.0 mL serum minimum
- Stability
- Room temperature: 7 days; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 3 months; Protect from light
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 1–24 hours
- Order
- routine
What is the Alkaline Phosphatase (ALP) test?
The Alkaline Phosphatase (ALP) test is a blood test that measures the level of ALP, an enzyme (a protein that helps chemical reactions in your body) primarily produced in your liver and bones. This test is commonly included in a group of tests called a liver function panel or comprehensive metabolic panel.
Why is this test performed?
Your healthcare provider may order an ALP test to: check for liver diseases or damage, evaluate symptoms like jaundice (yellowing of skin or eyes), abdominal pain, or unexplained fatigue, monitor existing liver conditions, or assess bone disorders such as bone disease or vitamin D deficiency.
How is the test done?
A healthcare professional will draw a small sample of blood from a vein in your arm. The sample is sent to a laboratory for analysis. You typically do not need to fast before this test, though your doctor may ask you to avoid certain medications or supplements that could affect the results.
Understanding your results
Normal ALP levels vary depending on your age, sex, and the laboratory that processes the test. Generally, normal adult ranges are between 20 to 140 U/L, but children and teenagers typically have higher levels due to bone growth. Your doctor will explain what your specific results mean in the context of your overall health.
Reference range
40-129 U/Lnot specified
No special preparation or fasting required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Frequently asked questions
Do I need to fast before the ALP test?
What does a high ALP level mean?
Can medications affect ALP test results?
Is the ALP test dangerous?
How often should I have this test?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 10, 2026. · Read our editorial policy