24-Hour Urinary Retinol Binding Protein (RBP) Mass Concentration
This test measures the amount of retinol binding protein (RBP) in your urine over a 24-hour period. It helps assess how well your kidneys filter and excrete RBP, which carries vitamin A in your blood.
["This test may help diagnose or monitor kidney function related to RBP metabolism."]
Key facts at a glance
- LOINC
- 96406-4
- Short code
- Retinol Bind Prot 24h Ur-mCnc
- Synonyms
- Retinol Bind Prot 24h Ur-mCnc
- Category
- chemistry
- 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
Why Is This Test Done?
Your healthcare provider may order this test if you have symptoms of kidney disease, such as changes in urine output, swelling, or fatigue. It may also be used to evaluate conditions affecting vitamin A metabolism or kidney function in rare genetic disorders.
What Does the Test Measure?
RBP is a protein that transports vitamin A in your blood. When your kidneys filter RBP, it appears in urine. This test quantifies the total RBP excreted over 24 hours, giving insight into kidney function and vitamin A handling.
Sample Collection and Preparation
You’ll collect all urine for a full 24-hour period, typically starting after urinating at midnight the night before. Empty your bladder at the start and end times, then collect every urine sample in a container. Seal and refrigerate the samples until lab processing.
What to Expect Before the Test
No special preparation is needed, but avoid excessive vitamin A supplements or certain medications that may affect RBP levels. Stay hydrated but avoid excessive fluid intake that could dilute urine.
Reference range
NCBI: Vitamin A 38-98 µg/dLN/A
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.
Elevated levels may indicate kidney dysfunction or conditions like Fanconi syndrome, where kidney reabsorption of proteins is impaired. Low levels could suggest vitamin A deficiency or kidney disease affecting RBP excretion. This test is less commonly used than blood RBP but may be critical in specific genetic or metabolic evaluations.
Short name
24h Urinary RBP Mass
Frequently asked questions
What causes abnormal RBP levels in urine?
How is this test different from a blood RBP test?
Can diet affect this test result?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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