What this test measures
Vitamin A circulates in serum mainly as retinol bound to retinol-binding protein (RBP). The body stores most vitamin A in the liver — serum levels are kept within a narrow range until liver stores are severely depleted, so the test is more useful for detecting overt deficiency or excess than for detecting marginal status.
Dietary vitamin A comes from animal sources (preformed retinol — liver, eggs, dairy) and plant sources (provitamin A carotenoids — carrots, leafy greens, mango, papaya, sweet potato). The test reports total retinol in serum.
Why it matters
Vitamin A deficiency remains a public health problem in parts of India, especially in children — it is a leading preventable cause of childhood blindness and increases mortality from measles and diarrhoea. The National Vitamin A Prophylaxis Programme gives high-dose vitamin A every 6 months to children aged 9 months to 5 years for this reason.
Adult deficiency in India is most often seen in chronic liver disease (the liver stores and processes vitamin A), pancreatic insufficiency, cystic fibrosis, severe malabsorption (coeliac, bariatric surgery), and chronic alcohol use. Symptoms — night blindness, dry eyes (xerophthalmia), Bitot's spots, dry skin, increased infection risk. Toxicity is uncommon but seen with high-dose supplements, isotretinoin (acne drug), and rarely large amounts of liver in the diet.
How to prepare
Fasting morning sample (8–12 hours) preferred — vitamin A varies with recent meals, especially fatty meals. Avoid vitamin A supplements for at least 24 hours (longer for high-dose supplements). Mention recent illness (acute infection lowers retinol-binding protein and hence serum retinol).
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Vitamin A (Retinol) (µg/dL)[1][2] | 30 – 80 (method- and age-dependent) | Deficiency (<20 µg/dL — severe). Causes — inadequate dietary intake (rare in adults, common in children in deprived areas), malabsorption (fat is needed for absorption — cystic fibrosis, pancreatic insufficiency, bariatric surgery, coeliac, IBD), chronic liver disease (impaired storage and transport), alcohol use, zinc deficiency (zinc is needed for RBP synthesis). Symptoms — night blindness, dry eyes, Bitot's spots, dry skin, recurrent infections. | Hypervitaminosis A (>100 µg/dL). Acute toxicity — high single dose: headache, vomiting, blurred vision, raised intracranial pressure. Chronic toxicity — sustained high intake: dry skin, hair loss, bone pain, liver injury, raised intracranial pressure. Causes — over-supplementation, isotretinoin therapy, large amounts of animal liver. Teratogenic in pregnancy — vitamin A supplements above 10,000 IU/day are not safe in pregnancy. |
Vitamin A status — clinical mapping
| Retinol (µg/dL) | Status | Symptoms | Action |
|---|---|---|---|
| < 10 | Severe deficiency | Xerophthalmia, Bitot's spots, night blindness, keratomalacia | High-dose supplementation under medical guidance + treat cause |
| 10 – 19 | Moderate deficiency | Night blindness, dry skin, recurrent infections | Supplementation + dietary counselling |
| 20 – 29 | Marginal | Often asymptomatic; may have subclinical immune compromise | Dietary improvement, re-check |
| 30 – 80 | Sufficient | Normal | No action; continue varied diet |
| > 100 | Excess / toxicity | Headache, dry skin, hair loss, bone pain | Stop supplements; investigate source |
Frequently asked questions
Who should get a vitamin A test?
Anyone with night blindness, dry eyes, chronic liver disease, malabsorption (cystic fibrosis, IBD, post-bariatric surgery), recurrent severe infections (especially in children), pancreatic insufficiency, or suspected toxicity from supplements / isotretinoin.
Do I need to fast?
A fasting morning sample is preferred. Avoid vitamin A supplements for 24 hours.
Why is vitamin A deficiency a concern in Indian children?
It remains a leading preventable cause of childhood blindness and raises mortality from measles and diarrhoea. India runs a National Vitamin A Prophylaxis Programme — high-dose vitamin A every 6 months between 9 months and 5 years of age.
Can vegetarians get enough vitamin A?
Yes — dark leafy greens, carrots, sweet potato, mango, papaya and red palm oil are good sources of provitamin A carotenoids. Dairy and eggs add preformed vitamin A. Pure vegans should ensure regular intake of orange / green vegetables.
Is vitamin A safe in pregnancy?
Dietary vitamin A and beta-carotene are safe. Supplemental retinol above 10,000 IU/day is teratogenic and should be avoided. Isotretinoin (acne) is strictly contraindicated in pregnancy.
Can vitamin A toxicity damage the liver?
Yes — chronic excess (commonly from high-dose multivitamins or animal liver in some traditional remedies) can cause hepatotoxicity. Stopping the source usually allows recovery.
Why does liver disease affect vitamin A?
The liver stores 80% of body vitamin A and produces retinol-binding protein. Chronic liver disease (cirrhosis, alcoholic) impairs both, often causing deficiency.
Related Vitamins / Nutrition tests
Tests commonly ordered alongside VITAMIN A, or that help interpret an unexpected result.
Sources & references
- NIH Office of Dietary Supplements — Vitamin A · accessed 2026-05-30T00:00:00.000Z
- NCBI StatPearls — Vitamin A Deficiency · accessed 2026-05-30T00:00:00.000Z
- ICMR Recommended Dietary Allowances for Indians 2020 · accessed 2026-05-30T00:00:00.000Z
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