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Hydroxyproline-to-Creatinine Ratio, Urine

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

Measures hydroxyproline relative to creatinine in urine to assess collagen breakdown, particularly from bone, while accounting for urine concentration.

Quick summary

["This urine test can help evaluate increased collagen breakdown, but abnormal results require interpretation alongside other clinical findings."]

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

Key facts at a glance

LOINC
28601-3
Short code
OH-Proline/Creat Ur-Rto
Synonyms
OH-Proline/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?

Hydroxyproline is an amino acid released when collagen is broken down. This test measures urinary hydroxyproline and compares it with urinary creatinine, which helps account for variations in urine concentration.

Why might I need this test?

It may be used to evaluate conditions involving increased bone turnover or collagen breakdown. It is now less commonly used because newer blood and urine markers can provide more specific information in many situations.

How is the test performed?

A urine sample is collected and analyzed for hydroxyproline and creatinine. The laboratory then calculates the hydroxyproline-to-creatinine ratio.

How do I prepare for the test?

Follow the collection instructions provided by the laboratory, including whether a first-morning or timed urine sample is required. Tell your clinician if you are pregnant, have an active bone fracture, or are healing from surgery, as these can affect the result.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urine hydroxyproline/creatinine ratio

Frequently asked questions

What does a high hydroxyproline-to-creatinine ratio mean?
It may suggest increased collagen breakdown, including bone breakdown, but the finding is not specific to one condition. Other laboratory tests and clinical information are usually needed to determine the cause.
Is this the same as a urine protein test?
No. This test measures hydroxyproline, a product of collagen breakdown, and compares it with creatinine. A standard urine protein test measures protein in the urine.
Do I need to collect urine for a specific amount of time?
The collection method depends on the laboratory's instructions, which may call for a single urine sample or a timed collection. Follow the provided directions carefully because the method can affect interpretation.
  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