Alkaline Phosphatase (ALP) Test
A blood test that measures the amount of alkaline phosphatase, an enzyme found primarily in your liver and bones, in a sample of your blood. Your doctor may order it to help diagnose, evaluate, or monitor conditions that affect these organs.
{"Measures ALP enzyme from liver and bone sources in your blood","Elevated levels may indicate liver disease, bile duct blockage, or bone disorders","A simple blood draw is all that's needed - no special preparation typically required","Results help doctors distinguish between liver and bone-related conditions","Often part of a routine liver function test panel"}
Key facts at a glance
- LOINC
- 43708-7
- Short code
- ALP
- Synonyms
- ALP Liver+Bone SerPl Ql
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or plain red top tube
- Units
- not specified
- Ref low
- 20
- Ref high
- 140
- Critical range
- — – 500 not specified
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Spectrophotometric enzymatic assay using p-nitrophenyl phosphate (PNPP) as substrate
- CPT
- 84075
- SNOMED
- 270000006
- Specimen volume
- 0.5-2 mL serum minimum
- Stability
- Room temperature: 7 days; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 3 months
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 20
- TAT
- 1–24 hours
- Order
- routine
What is this test?
The Alkaline Phosphatase (ALP) test measures the level of ALP enzyme in your blood. ALP is produced by various tissues in your body, with the liver and bones being the two major sources. This specific test helps determine whether elevated ALP is coming from your liver or your bones, which is crucial for proper diagnosis.
Why is it important?
Alkaline phosphatase plays a key role in breaking down proteins in your body. When liver cells or bone cells are damaged or overactive, they release more ALP into your bloodstream. By measuring these levels, your doctor can identify problems with your liver, gallbladder, or bones.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then sent to a laboratory for analysis. The test is usually part of a comprehensive metabolic panel or liver function test.
Understanding your results
Normal ALP levels vary based on age, gender, and blood type. Generally, adults have lower ALP levels than growing children and adolescents. Your doctor will interpret your results based on your individual health profile and may order additional tests to confirm a diagnosis.
Reference range
Negativenot specified
No special preparation required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings2
Frequently asked questions
Do I need to fast before this test?
Can medications affect my ALP levels?
How long does it take to get results?
Why would my doctor order this specific test?
Are there any risks with 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