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Urine Phenylpyruvate-to-Creatinine Ratio

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

A urine test used to help screen for elevated phenylalanine associated with phenylketonuria, especially in newborns and infants.

Quick summary

["An elevated result may suggest phenylketonuria and should be confirmed with appropriate blood testing."]

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

Key facts at a glance

LOINC
13794-3
Short code
Phenylpyruvate/Creat Ur
Synonyms
Phenylpyruvate/Creat Ur
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 test measures phenylpyruvate relative to creatinine in urine. Creatinine is used as a reference for urine concentration, which can vary widely from sample to sample.

Why might I need this test?

It may be used as a screening test for phenylketonuria, an inherited condition in which the body cannot properly process phenylalanine. It can also help monitor infants being evaluated or treated for this condition.

How is the test performed?

A urine sample is collected and tested in a laboratory to determine the amount of phenylpyruvate compared with creatinine. The ratio can help reduce the effect of differences in urine concentration.

How do I prepare for the test?

Follow the laboratory or newborn-screening instructions for urine collection. The sample may be collected in a clean container or from a diaper with a collection method, depending on the laboratory's instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine phenylpyruvate/creatinine ratio

Frequently asked questions

Is this the same as a blood phenylalanine test?
No. This is a urine screening test. Blood phenylalanine testing is commonly used to confirm suspected phenylketonuria and monitor treatment.
Why is creatinine included in the result?
Creatinine helps show how concentrated the urine is. Comparing phenylpyruvate with creatinine makes the result less dependent on variations in urine volume or concentration.
What should I do if the result is abnormal?
Contact your healthcare professional promptly. Further testing, usually including measurement of blood phenylalanine, may be needed to determine whether treatment is necessary.
  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