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Serum Vitamin A (Retinol) Concentration

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

This test measures the amount of vitamin A (retinol) in your blood serum, an important nutrient for vision, immune function, and cell growth.

Quick summary

["Vitamin A supports your health by helping your eyes, immune system, and skin function properly."]

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

Key facts at a glance

LOINC
100839-0
Short code
Vitamin A/Retinol Bind Prot SerPl-Rto
Synonyms
Vitamin A/Retinol Bind Prot SerPl-Rto
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
30
Ref high
100
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 order this test if you have symptoms like night blindness, frequent infections, dry skin, or if you’re at risk for vitamin A deficiency (e.g., due to poor diet, malabsorption issues, or certain medical conditions). It may also be checked during pregnancy or if you’re taking medications that affect vitamin A levels.

What to Expect Before the Test

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

What the Results Mean

Results are compared to standard reference ranges for healthy adults. Low levels may indicate deficiency, while very high levels could signal liver disease or other conditions. Your provider will interpret results in the context of your overall health.

Common Causes of Abnormal Results

Low vitamin A levels can result from poor diet, liver disease, malabsorption (e.g., celiac disease), chronic kidney disease, or certain medications. High levels may be linked to liver problems or excessive vitamin A supplements.

Reference range

NCBI: Vitamin D 30-100 ng/mL (sufficient)N/A

Specimen: serum

Fasting for 8-12 hours preferred for some tests. Inform about supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Vitamin A Level

Frequently asked questions

What happens if my vitamin A level is low?
A low vitamin A level may mean you’re not getting enough vitamin A through your diet or your body isn’t absorbing it properly. This can weaken your immune system, cause vision problems, and slow wound healing. Your provider may recommend dietary changes, supplements, or further testing to identify the cause.
Can high vitamin A levels be dangerous?
Yes, very high vitamin A levels (hypervitaminosis A) can cause headaches, nausea, bone pain, or even liver damage. This is rare with natural vitamin A but can happen with excessive supplements. If your results are high, your provider may investigate underlying conditions like liver disease.
How often should I get this test?
Your provider will determine how often you need this test based on your health status, symptoms, or risk factors. For example, pregnant women, those with liver disease, or people with malabsorption disorders may need more frequent monitoring.
  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