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Phenyl Lactate-to-Creatinine Ratio, Urine

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

A urine test that measures phenyl lactate relative to creatinine, helping evaluate phenylalanine metabolism and monitor conditions such as phenylketonuria.

Quick summary

["This test helps assess how well phenylalanine is being metabolized, particularly in people with phenylketonuria."]

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

Key facts at a glance

LOINC
13792-7
Short code
Phenyllactate/Creat Ur
Synonyms
Phenyllactate/Creat Ur
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?

The urine phenyl lactate-to-creatinine ratio measures the amount of phenyl lactate in urine relative to creatinine. Creatinine helps account for differences in urine concentration.

Why might I need this test?

This test may be used to evaluate phenylalanine metabolism, especially in people with phenylketonuria (PKU). It can help monitor dietary treatment and biochemical control of the condition.

How is the test performed?

A urine sample is collected and analyzed in a laboratory. The laboratory measures phenyl lactate and creatinine in the sample and calculates their ratio.

How do I prepare for the test?

Follow the collection instructions provided by your healthcare professional or laboratory. Your clinician may give specific instructions about diet, medication, and the timing of urine collection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine phenyl lactate ratio

Frequently asked questions

What is phenyl lactate?
Phenyl lactate is a substance formed when phenylalanine, an amino acid, is broken down. Its amount in urine can reflect how well phenylalanine is being metabolized.
Why is the result divided by creatinine?
Dividing by creatinine helps adjust for variations in urine concentration. This makes results from samples with different water content more comparable.
Does this test replace blood phenylalanine monitoring?
No. Urine results are used with blood tests and clinical information to assess and monitor phenylketonuria. Your healthcare team determines the full monitoring plan.
  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