Home Biomarkers Vitamin A

Vitamin A

Vitamins Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: Vitamins

Overview

Vitamin A refers mainly to circulating retinol, a fat‑soluble vitamin essential for vision (especially night vision), epithelial integrity, immune function and growth. The blood test measures serum retinol (or retinol-binding protein) to assess body vitamin A status. Low levels suggest deficiency that can cause night blindness, xerosis/keratomalacia, recurrent infections and growth problems; high levels suggest excess intake or liver release and risk of toxicity (headache, liver injury, intracranial hypertension, teratogenicity). Results vary by age, pregnancy, nutritional status and acute illness (inflammation lowers serum retinol), and children and pregnant women have different requirements.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: Vitamins - Symptoms prompting test: night blindness, dry eyes, recurrent infections, poor growth, unexplained liver symptoms, or suspected supplement overdose - Conditions diagnosed/monitored: nutritional deficiency, malabsorption, chronic liver disease, hypervitaminosis A - Reasons for abnormal levels: inadequate dietary intake, fat‑malabsorption, inflammation (lowers retinol), excessive supplementation or liver release - Biological meaning: low = depleted stores and impaired vision/immune function; high = excessive storage/toxicity risk - Lifestyle/family history: restrictive diets, alcoholism, bariatric surgery, malabsorption syndromes, family history of liver disease

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Understanding Test Results

Serum retinol <10 µg/dL (<0.35 µmol/L) indicates severe deficiency and high risk for xerophthalmia and serious immune compromise.
Levels 10–20 µg/dL (0.35–0.7 µmol/L) indicate deficiency or marginal status and warrant nutritional intervention.
Values within 20–80 µg/dL (0.7–2.8 µmol/L) are generally adequate for most people.
Persistent concentrations substantially above the reference range (for example >100 µg/dL or >3.5 µmol/L) suggest excessive intake or mobilization from liver stores and raise concern for hypervitaminosis A (headache, hepatic dysfunction, intracranial hypertension, teratogenic risk); however, serum retinol is homeostatically controlled and can be lowered during acute inflammation, so results must be interpreted with clinical context, repeat testing and assessment of diet, supplements and liver function.

Normal Range

20-80 µg/dL OR 0.7-2.8 µmol/L

FAQs

Q: Which food is rich in vitamin A?

A: Liver (beef, chicken) is the richest source of vitamin A. Other excellent sources include sweet potatoes, carrots, spinach, kale, pumpkin, and red bell peppers, which supply provitamin A (beta‑carotene). Eggs, milk and fortified dairy products also provide preformed vitamin A. Including a mix of these animal and plant foods helps meet vitamin A needs safely.

Q: What is the vitamin A good for?

A: Vitamin A supports healthy vision—particularly night vision—and maintains the health of the eyes’ surface tissues. It’s essential for immune function, helping the body fight infections, and for growth, reproduction and cell differentiation. Provitamin A (beta‑carotene) acts as an antioxidant. Deficiency can cause night blindness and dry eyes; excess intake can be toxic, so balance through diet or supervised supplements is important.

Q: What happens if vitamin A is low?

A: Vitamin A deficiency causes night blindness and can progress to xerophthalmia, keratinization of the conjunctiva and cornea, and permanent blindness. It weakens immune function, increasing susceptibility to respiratory and diarrheal infections and raising child mortality risk. In children it can stunt growth; adults may develop dry, scaly skin, poor wound healing, and reproductive problems.

Q: Which fruit is the king of vitamin A?

A: Mango is widely regarded as the \

Q: How can I increase vitamin A?

A: Eat more vitamin A–rich foods: liver and oily fish for preformed vitamin A; eggs, dairy and fortified products; and orange/yellow vegetables and fruits (carrots, sweet potato, pumpkin) plus dark leafy greens for beta‑carotene. Cooking and eating with a little fat boosts absorption. Use supplements only if recommended—avoid high‑dose retinol in pregnancy and consult your clinician before taking vitamins.

Q: How to check vitamin A deficiency?

A: Check for vitamin A deficiency by noting symptoms (night blindness, dry or irritated eyes, Bitot’s spots, dry skin, frequent infections) and reviewing diet. A clinician can perform an eye exam and order blood tests (serum retinol or retinol-binding protein) to confirm low levels. High‑risk groups (young children, pregnant women) should seek medical assessment for testing and prompt treatment.