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Threonine/Creatinine Ratio, Urine

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

A urine test that measures threonine relative to creatinine, helping evaluate how well the kidneys handle this amino acid.

Quick summary

["An elevated ratio may indicate impaired kidney reabsorption of threonine, including in Hartnup disease."]

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

Key facts at a glance

LOINC
30057-4
Short code
Threonine/Creat Ur-Rto
Synonyms
Threonine/Creat Ur-Rto
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 the amount of threonine, an amino acid, in urine compared with the amount of creatinine. The ratio helps account for differences in urine concentration.

Why might I need this test?

It may be used when evaluating Hartnup disease or other conditions that affect how the kidneys transport amino acids. It may also be part of the assessment of an infant with unexplained symptoms or poor growth.

How is the test performed?

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

How do I prepare for the test?

No special preparation is usually needed. Follow the laboratory's instructions about the type and timing of urine collection, and tell the care team about medicines, supplements, or unusual changes in diet.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine threonine/creatinine ratio

Frequently asked questions

What does the urine threonine-to-creatinine ratio measure?
It compares the amount of threonine with the amount of creatinine in urine. Creatinine is used as a marker of urine concentration.
What conditions can cause an elevated result?
An elevated ratio may occur when kidney transport of threonine is impaired, particularly in Hartnup disease. Diet, age, and other kidney-related factors can also affect the result.
Do I need to fast for this test?
Fasting is generally not required, but collection instructions may vary by laboratory. If a specific diet or timed collection has been requested, follow those instructions exactly.
  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