Skip to content

Phenylpyruvic Acid, Urine — Liquid Chromatography-Mass Spectrometry, Mass Concentration

Published: August 9, 2026Updated: August 16, 2026

A urine test that measures phenylpyruvic acid, a substance related to phenylalanine metabolism, using LC-MS.

Quick summary

["This test measures phenylpyruvic acid in urine to help evaluate phenylalanine metabolism."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
104675-4
Short code
PPAA Ur LC/MS/MS-mCnc
Synonyms
PPAA Ur LC/MS/MS-mCnc
Category
liver
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
lc-ms-ms
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 measures the amount of phenylpyruvic acid in your urine using liquid chromatography-mass spectrometry (LC-MS). Phenylpyruvic acid is a breakdown product related to the amino acid phenylalanine.

Why might I need this test?

This test may be ordered to help evaluate a possible disorder of phenylalanine metabolism, including phenylketonuria. It is generally interpreted alongside symptoms, other laboratory results, and dietary information.

How is the test performed?

A urine sample is collected and analyzed in the laboratory with LC-MS. The result reports the concentration of phenylpyruvic acid in the urine.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional. Do not make major changes to your diet or take extra supplements without medical advice, because diet and medicines may affect metabolic test results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

An increased amount of urine phenylpyruvic acid may occur when phenylalanine metabolism is impaired, as can happen in untreated or poorly controlled phenylketonuria. Urine concentration can also vary with hydration, so the result should be interpreted with the collection method and other laboratory findings. This test alone does not establish a diagnosis.

Short name

Urine phenylpyruvic acid

Frequently asked questions

What does phenylpyruvic acid measure?
It measures the amount of phenylpyruvic acid, a substance produced during phenylalanine metabolism, in a urine sample.
Can an elevated result indicate phenylketonuria?
Yes, elevated urine phenylpyruvic acid can occur with phenylketonuria, particularly when the condition is not well controlled. Blood tests and clinical findings are usually needed to confirm the diagnosis.
Do I need to fast before this test?
Fasting is not routinely required for every urine collection, but specific instructions may apply. Follow your clinician's or laboratory's directions and tell them about major dietary or medication changes.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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