Urine Alkaline Phosphatase Test
This urine test measures the amount of alkaline phosphatase, an enzyme found in tissues throughout your body, to help evaluate the health of your kidneys and urinary tract. Your healthcare provider may order it to look for kidney damage, urinary tract infections, blockages, or other conditions affecting these areas. It is a simple, non-invasive test that only requires a urine sample, and the results can help your provider decide whether you need further testing or treatment.
{"Alkaline phosphatase is an enzyme found in kidneys, liver, and bones","This test helps detect kidney damage or urinary tract problems","Abnormal levels may indicate kidney injury, urinary obstruction, or certain diseases","The test requires a simple urine sample","Results are compared with reference ranges to determine if levels are normal"}
Key facts at a glance
- LOINC
- 16337-8
- Short code
- ALP urine
- Synonyms
- ALP Ur-cCnc
- Category
- chemistry
- Sample
- urine
- Container
- Clean urine container ( sterile, graduated)
- Units
- not specified
- Ref low
- 1
- Ref high
- 19
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Enzymatic colorimetric assay using p-nitrophenyl phosphate (pNPP) as substrate
- CPT
- 82164
- SNOMED
- 313295008
- Specimen volume
- 5-10 mL minimum; 10-15 mL preferred
- Stability
- Refrigerated (2-8°C) for up to 7 days; frozen (-20°C) for longer storage; stability may vary by methodology
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 1–24 hours
- Order
- routine
What is this test?
The urine alkaline phosphatase test measures the amount of alkaline phosphatase, an enzyme, in your urine. Alkaline phosphatase is produced by various tissues in the body, including the kidneys, liver, intestines, and bones. When kidney tissues are damaged, alkaline phosphatase leaks into the urine, making it a useful marker for detecting kidney injury or urinary tract problems.
Why is this test done?
Your healthcare provider may order this test to: evaluate kidney function, detect kidney damage from injury or disease, monitor kidney recovery after surgery or treatment, help diagnose urinary tract infections or obstructions, and assess conditions that may affect the kidneys such as diabetes or high blood pressure.
How is the test performed?
The test uses a simple urine sample. You will be asked to provide a clean catch urine sample in a sterile container. For a clean catch, you clean your genital area before collecting the urine midstream. The sample is then sent to a laboratory where technicians measure the alkaline phosphatase levels using special chemical methods.
Understanding your results
Results are typically reported as units per liter (U/L). Normal ranges vary by laboratory, but generally, low or undetectable levels are considered normal. Elevated levels may indicate kidney damage, urinary tract infection, kidney stones, prostate issues, or certain bone disorders. Your healthcare provider will interpret your results based on your overall health and other test findings.
Reference range
Laboratory-specific; not routinely established for clinical usenot specified
No special preparation required; random urine specimen preferred unless timed collection specified
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated urine alkaline phosphatase levels may indicate acute kidney injury, chronic kidney disease, urinary tract infection, kidney stones, bladder infection, prostate inflammation, or certain bone diseases. This test is particularly useful in detecting early kidney damage before other symptoms appear. It is often used alongside other kidney function tests (like creatinine and blood urea nitrogen) to get a complete picture of kidney health.
Low levels of alkaline phosphatase in urine are generally not a concern and may simply indicate normal kidney function. However, extremely low levels combined with other abnormal findings might warrant further investigation.
Frequently asked questions
Do I need to fast before this test?
Are there any risks to this test?
What can affect my test results?
How long does it take to get results?
What happens if my results are abnormal?
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 16, 2026. · Read our editorial policy