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Serum or Plasma Retinol Binding Protein Concentration

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

This test measures the level of retinol binding protein (RBP) in your blood. RBP helps transport vitamin A, a vital nutrient for vision, immune function, and cell growth.

Quick summary

["RBP levels can indicate vitamin A status and potential deficiencies."]

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

Key facts at a glance

LOINC
82592-7
Short code
Mid Retics NFr Auto
Synonyms
Mid Retics NFr Auto
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
automated-count
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
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 night blindness, dry skin, or frequent infections. It could also be used to monitor vitamin A levels in patients with certain medical conditions, like chronic kidney disease, or those on specific diets.

What to Expect During the Test

A simple blood draw is typically used to collect the sample. You may feel a slight pinch when the needle is inserted, but most people find it brief and manageable. No special preparation is needed, but fasting may be advised depending on your specific test order.

Common Causes of Abnormal Results

Low levels of RBP might suggest vitamin A deficiency, liver disease, or kidney problems. High levels could be associated with certain genetic conditions or specific medications. Always discuss any concerns with your healthcare provider.

How Results Are Interpreted

Results are compared to standard ranges for your age and health status. Your provider will interpret these results in the context of your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Retinol Binding Protein (RBP)

Frequently asked questions

What does a low RBP level mean?
A low RBP level may indicate a vitamin A deficiency, which can affect your vision, immune system, and overall health. It can also be linked to liver or kidney issues. Your doctor may recommend vitamin A supplements or further tests to identify the underlying cause.
What does a high RBP level mean?
High RBP levels can sometimes be associated with genetic conditions or certain medications. In some cases, it may indicate a need for further evaluation, especially if you have symptoms like fatigue or unexplained weight loss. Your healthcare provider will guide you on next steps based on your specific situation.
Is fasting required for this test?
Fasting requirements may vary. Some tests do not require fasting, while others might. Always follow your healthcare provider’s instructions. If fasting is required, it’s important to do so to ensure accurate results.
  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