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Phytanic Acid/Creatinine Ratio, Urine

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

A urine test that measures phytanic acid relative to creatinine. It can help evaluate suspected disorders of phytanic acid metabolism, including Refsum disease.

Quick summary

["An elevated urine phytanic acid-to-creatinine ratio may suggest impaired phytanic acid metabolism, but it does not establish a diagnosis by itself."]

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

Key facts at a glance

LOINC
47726-5
Short code
Phytanate/Creat Ur-sRto
Synonyms
Phytanate/Creat Ur-sRto
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86038
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 phytanic acid in urine and compares it with the amount of creatinine in the same sample. Creatinine is used as a marker of urine concentration, so the ratio helps reduce the effect of variations in how concentrated the urine is.

Why might I need this test?

The test may be used when a clinician is evaluating a possible disorder of phytanic acid metabolism. This includes rare inherited conditions such as Refsum disease, which can affect nerves, coordination, hearing, and vision.

How is the test performed?

A urine specimen is collected in the container provided by the laboratory. The laboratory measures phytanic acid and creatinine and reports their ratio. The type of urine collection and the laboratory analysis method may vary.

How do I prepare for the test?

Follow the laboratory's instructions for urine collection, including whether a spot or timed sample is required. Do not make major dietary or supplement changes specifically for this test unless your healthcare professional advises you to do so.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine phytanic acid ratio

Frequently asked questions

What does the phytanic acid-to-creatinine ratio show?
It shows the amount of phytanic acid in urine relative to creatinine. The ratio helps account for differences in urine concentration.
Why is phytanic acid tested in urine?
Urine testing can help identify reduced breakdown or increased elimination of phytanic acid, which is relevant when evaluating rare metabolic disorders.
Does an abnormal result confirm a genetic disorder?
No. An abnormal result may prompt additional testing, genetic evaluation, or specialist review, but it is not diagnostic on its own.
  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