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Serum or plasma concentration of vitamin A (retinol)

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

This test measures the amount of vitamin A, a fat-soluble nutrient essential for vision, immune function, and cell growth, in your blood.

Quick summary

["Vitamin A helps protect your eyes and supports overall health; low levels may indicate nutritional deficiencies or medical conditions."]

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

Key facts at a glance

LOINC
41867-3
Short code
vWF Ag PPP-aCnc
Synonyms
vWF Ag PPP-aCnc
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
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 Is This Test Done?

Your healthcare provider may order this test if you have symptoms like night blindness, dry skin, frequent infections, or if you’re at risk for vitamin A deficiency (e.g., poor diet, malabsorption issues). It can also be part of routine check-ups or evaluations for liver disease or certain genetic disorders.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the draw if your lab uses a different method. Avoid taking high-dose vitamin A supplements 24 hours before testing.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The blood sample is sent to a lab to measure vitamin A levels using a sensitive immunoassay or enzymatic method.

What the Results Mean

Results are compared to a reference range for healthy adults, but exact values can vary by lab. Low levels may signal deficiency, while very high levels could indicate overconsumption or certain liver conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Vitamin A level

Frequently asked questions

What Are Common Causes of Low Vitamin A Levels?
Low vitamin A levels can result from poor diet (e.g., limited intake of liver, carrots, or fortified foods), malabsorption disorders (like celiac disease), liver disease, or certain medications that interfere with absorption.
What Are Common Causes of High Vitamin A Levels?
Excess vitamin A can occur from overconsumption of supplements or megadoses of vitamin A-rich foods. Rarely, it may be linked to liver disease or genetic disorders affecting fat metabolism.
How Often Should I Get This Test?
Your provider will determine frequency based on your health status. Typically, it’s not routine unless you have symptoms or risk factors for deficiency or toxicity.
  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