Vitamins & minerals
Vitamin A
LOINC 2923-1 · mcg/dL
Ranges
Reference range: 30–95 mcg/dL
What it is
Vitamin A is a fat-soluble vitamin important for vision, immune function, skin and cell growth.
Why it matters
The test checks vitamin A status, relevant to eye health, immunity and, in excess, toxicity.
What high values can mean
A higher value usually results from high supplement intake and can be harmful in excess.
What low values can mean
A lower value can affect night vision and immunity and may follow poor intake or absorption problems.
How to improve it
A varied diet usually provides enough; supplements should be used cautiously because too much is harmful.
Food & lifestyle
Liver, dairy, eggs and orange/green vegetables (as beta-carotene) provide vitamin A.
Preparing for the test
A blood test; fasting may be requested — follow your lab's instructions.
When to talk to a doctor
Discuss a low or high vitamin A with a doctor, especially before taking high-dose supplements.
Sources
- NIH Office of Dietary Supplements
- MedlinePlus (NIH)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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