Phenylacetate and Creatinine, Urine and Stool
Measures phenylacetate, a product of phenylalanine metabolism, and creatinine in urine and stool. This may help assess metabolic activity and treatment or dietary control in phenylalanine metabolism disorders.
["These results can help evaluate phenylalanine metabolism and monitor control of related metabolic disorders."]
Key facts at a glance
- LOINC
- 25124-9
- Short code
- Phenylacetate/Creat Ur-sRto
- Synonyms
- Phenylacetate/Creat Ur-sRto
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This laboratory test measures phenylacetate and creatinine in urine and stool. Phenylacetate is a product of phenylalanine metabolism, while creatinine is commonly measured to help interpret urine results independently of urine concentration.
Why might I need this test?
This test may be ordered for people with phenylketonuria or another condition affecting phenylalanine metabolism. It can help clinicians assess dietary or treatment effectiveness and identify changes in the body's handling of phenylalanine.
How is the test performed?
Urine and stool samples are collected as directed and sent to a laboratory for analysis. The laboratory measures the amount of phenylacetate and creatinine present in each sample.
How do I prepare for the test?
Follow the collection instructions provided by your healthcare professional, including the amount and timing of urine and stool samples collected. Do not change your diet or medication unless your clinician specifically instructs you to do so.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
An increased amount of phenylacetate relative to creatinine may indicate that phenylalanine is being broken down at a higher rate or that dietary or treatment control is inadequate. Results can also vary with diet, kidney function, intestinal bacteria, and sample collection, so they should be interpreted alongside the other parts of your metabolic evaluation.
Short name
Phenylacetate and Creatinine, Urine/Stool
Frequently asked questions
What does phenylacetate measure?
Why is creatinine included in the test?
Do I need to change my diet before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 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