Skip to content

Phenylactate-to-Creatinine Ratio, Urine

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

A urine test that measures phenylactate relative to creatinine, helping account for differences in urine concentration.

Quick summary

["This test can help assess phenylalanine metabolism, particularly when monitoring a metabolic condition such as phenylketonuria."]

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

Key facts at a glance

LOINC
25125-6
Short code
Phenyllactate/Creat Ur-sRto
Synonyms
Phenyllactate/Creat Ur-sRto
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Critical range
— – 4 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 the amount of phenylactate in urine relative to the amount of creatinine. Creatinine is used as a reference to help adjust for how concentrated or dilute the urine sample is.

Why might I need this test?

The test may be used along with blood and urine testing to evaluate phenylalanine metabolism. It is especially relevant in the care of people with phenylketonuria or related metabolic disorders.

How is the test performed?

A urine sample is analyzed to determine its phenylactate and creatinine concentrations. The laboratory then calculates a phenylactate-to-creatinine ratio, which can be more useful than a phenylactate measurement alone.

How do I prepare for the test?

A random urine sample is usually sufficient unless your clinician requests a timed collection. Follow the laboratory’s collection instructions and ask whether any medications, supplements, or dietary changes could affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine phenylactate-to-creatinine ratio

Frequently asked questions

Why is creatinine included in this urine test?
Creatinine helps show how concentrated the urine is. Including it allows phenylactate to be adjusted for dilution so results from different samples can be compared more reliably.
Does an abnormal result mean I have phenylketonuria?
No. An abnormal result can suggest a problem with phenylalanine metabolism, but it does not diagnose phenylketonuria by itself. Blood phenylalanine testing and other clinical information are also needed.
How is the urine sample collected?
The sample is usually collected in a clean, sterile container using the midstream clean-catch method. Follow any specific timing or storage instructions provided by the laboratory.
  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