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Retinol Binding Protein (RBP) in Serum/Plasma

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

This test measures the level of retinol-binding protein (RBP) in your blood. It helps assess how well your body is absorbing vitamin A.

Quick summary

["RBP levels can indicate vitamin A status and liver function."]

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

Key facts at a glance

LOINC
17525-7
Short code
Retinoate Ester SerPl-mCnc
Synonyms
Retinoate Ester SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms of vitamin A deficiency (such as dry skin, night blindness) or liver issues. It may also be used in monitoring conditions like malabsorption syndromes or kidney disease.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

RBP levels can vary based on vitamin A intake, liver function, and kidney function. Very low levels might suggest vitamin A deficiency or liver/kidney problems, while very high levels could indicate certain medical conditions.

Common Conditions Monitored

This test is often used to evaluate vitamin A metabolism, liver disease, or kidney function. It may also help diagnose or monitor conditions like cystic fibrosis or malnutrition.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

RBP is a protein that transports vitamin A in the blood. Low levels can signal underlying issues like liver dysfunction, kidney disease, or vitamin A deficiency. High levels may require further investigation to rule out conditions like nephrotic syndrome or certain liver disorders.

Short name

RBP

Frequently asked questions

What causes RBP levels to be low?
Low RBP levels can result from vitamin A deficiency, liver disease, kidney disease, or conditions affecting protein production in the body.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time.
Can diet affect RBP levels?
Yes, dietary vitamin A intake can influence RBP levels. High vitamin A consumption may temporarily raise RBP, while deficiencies can lower it.
  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