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Retinol-Binding Protein-to-Creatinine Ratio, Urine

Published: August 9, 2026Updated: August 17, 2026

A urine test that compares retinol-binding protein with creatinine to help assess kidney tubule function and protein loss.

Quick summary

["An elevated urinary RBP-to-creatinine ratio may indicate damage to the kidney's filtering tubules."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
96402-3
Short code
Retinol Bind Prot/Creat Ur
Synonyms
Retinol Bind Prot/Creat Ur
Category
kidney
Sample
urine
Container
Sterile urine container
Units
N/A
Ref low
38
Ref high
98
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 retinol-binding protein relative to creatinine in urine. Retinol-binding protein is a small protein that is normally retained by the kidneys, while creatinine helps account for how concentrated the urine is.

Why might I need this test?

It may be used to evaluate kidney tubule function, particularly in people with diabetes or conditions that may cause tubular injury. It can also help identify increased urinary loss of retinol-binding protein.

How is the test performed?

A urine sample is tested for retinol-binding protein and creatinine, and the results are used to calculate a ratio. Depending on the laboratory's instructions, this may involve a first-morning or other spot urine sample or a timed 24-hour collection.

How do I prepare for the test?

Fasting is usually not required, but you should follow the collection instructions provided by your healthcare professional. If a timed collection is requested, record when collection began and ended and collect all urine during that period.

Reference range

NCBI: Vitamin A 38-98 µg/dLN/A

Specimen: urine

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Urinary RBP/Creatinine Ratio

Frequently asked questions

What does the urinary RBP-to-creatinine ratio measure?
It compares the amount of retinol-binding protein in urine with the amount of creatinine. The ratio helps show whether retinol-binding protein is being lost in unusual amounts.
Does this test require fasting?
Fasting is generally not necessary. Follow any specific instructions given for a spot urine or 24-hour urine collection.
What might cause an elevated result?
An elevated result may reflect kidney tubule damage or reduced tubular reabsorption. Diabetes, oxidative stress, certain medications, and other kidney disorders are possible causes.
  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 17, 2026. · Read our editorial policy