Phenylpyruvic Acid, Urine — Qualitative, Substance Concentration
A urine test that detects phenylpyruvic acid, a phenylalanine breakdown product. It may help evaluate possible phenylketonuria, although newer blood-based testing is preferred.
["Detecting phenylpyruvic acid in urine may suggest impaired phenylalanine metabolism, but blood amino acid testing is needed for confirmation and monitoring."]
Key facts at a glance
- LOINC
- 99110-9
- Short code
- PPAA Ur Ql Scn
- Synonyms
- PPAA Ur Ql Scn
- Category
- liver
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- screen
- 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 test examines urine for the presence of phenylpyruvic acid, a substance produced when the body breaks down phenylalanine. It is primarily associated with the evaluation and monitoring of phenylketonuria, or PKU.
Why might I need this test?
A clinician may order this test when there is concern about untreated or poorly controlled PKU, especially in a child with developmental or neurological concerns. It may also be used to assess adherence to a phenylalanine-restricted diet, although blood-based phenylalanine measurements are generally more reliable.
How is the test performed?
A urine specimen is collected and analyzed for the presence of phenylpyruvic acid. Because this is a qualitative test, the result generally indicates whether the substance was detected rather than providing a precise concentration.
How do I prepare for the test?
Follow the laboratory's instructions for urine collection, including any requested timing or clean-catch procedure. Do not change your diet or phenylalanine intake specifically for this test unless your clinician directs you to do so.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Detecting phenylpyruvic acid in urine may indicate elevated phenylalanine and impaired phenylalanine metabolism, as can occur in untreated or inadequately controlled PKU. A negative result does not completely exclude PKU because urinary detection can vary. Plasma phenylalanine and tyrosine testing, along with newborn screening results, are generally used for confirmation and ongoing monitoring.
Short name
Urine Phenylpyruvic Acid
Frequently asked questions
What does a positive urine phenylpyruvic acid test mean?
Is this the same as newborn screening for PKU?
Can a negative result rule out phenylketonuria?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy