Vitamin A (Retinol)
Measures vitamin A (retinol) levels in blood to assess nutritional status and detect deficiency or toxicity that may affect vision, immune function, and overall health.
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What this test measures
The Vitamin A test measures the amount of retinol in the bloodstream. Vitamin A exists primarily as retinol, the active form, and provitamin A (beta-carotene) from plant sources, though this test specifically measures retinol levels. The test determines whether the body has enough vitamin A for normal physiological functions, including healthy vision, skin growth and integrity, bone formation, immune function, and reproduction.
Retinol is the primary form of vitamin A in humans, and this test measures its concentration in blood. A normal vitamin A blood level indicates adequate current stores, though it may not reflect liver reserves since the body maintains stable blood levels until stores become low. Serum retinol is typically maintained until hepatic stores are almost depleted, with values greater than 0.30 mg/L representing adequate liver stores and values less than 0.10 mg/L indicating deficiency.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing night blindness or difficulty seeing in low light conditions, as this may be an early sign of vitamin A deficiency that can progress to more serious vision problems.
- Those with dry eyes, dry skin, or frequent infections, since vitamin A plays a crucial role in maintaining healthy mucous membranes and supporting immune function.
- People with digestive disorders such as Crohn's disease, celiac disease, or liver disease that may impair absorption of fat-soluble vitamins like vitamin A.
- Individuals following restrictive diets or those with poor nutritional intake who may be at risk for vitamin A deficiency due to inadequate dietary sources.
- Those taking high-dose vitamin A supplements who want to monitor for potential toxicity, as excessive levels can cause serious health complications.
- Pregnant women or those planning pregnancy who need to ensure adequate but not excessive vitamin A levels, since both deficiency and excess can affect fetal development.
What to expect
Preparation
Fast for 12 hours before the test and avoid alcohol for 24 hours prior to collection. Schedule the blood draw for the morning before breakfast and before taking any medications. No vitamin supplements should be taken on the day of testing.
Sample Type
A healthcare professional will draw blood from a vein in the arm using a standard needle and collection tube. The process takes only a few minutes and involves minimal discomfort.
Collection
Visit any participating laboratory location during business hours. Check in at the front desk, and a phlebotomist will collect the blood sample. The sample will be protected from light and processed promptly to ensure accurate results.
Turnaround
Results are typically available within 2-5 business days after the laboratory receives the sample. Results will be securely delivered through the patient portal with no doctor visit required.
Understanding your results
Normal vitamin A levels typically range from 20 to 60 micrograms per deciliter (mcg/dL) or 0.69 to 2.09 micromoles per liter (micromol/L). Results outside this range may indicate deficiency or excess that could affect health and require further evaluation.
| Population | Reference Range | Notes |
|---|---|---|
| Adults | 20-60 mcg/dL (0.69-2.09 micromol/L) | Reference ranges established using fasting specimens and may vary slightly between laboratories |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Low vitamin A levels indicate a deficiency that can lead to night blindness and other complications. Symptoms of vitamin A deficiency may include difficulty seeing in low light or darkness, dry skin and hair, and weakened immune system making individuals more susceptible to infections. Vitamin A deficiency may occur when the body has trouble absorbing fats through the digestive tract, which can happen with certain medical conditions.
What does a “High” result mean?
High vitamin A levels typically indicate too much vitamin A circulating in the blood, which may lead to toxicity. Excessive vitamin A, usually from supplements or medications, can cause dizziness, headaches, nausea, and in serious cases may lead to coma or be life-threatening. In pregnant women, too much vitamin A can cause birth defects. Vitamin A toxicity can be dangerous and may cause symptoms including nausea, headaches, dizziness, and in severe cases, organ damage.
Privacy & confidentiality
All vitamin A test results are completely confidential and HIPAA-compliant. Results are delivered securely through your private patient portal and are never shared with insurance companies, employers, or added to your medical record without your consent. No doctor visit required for testing.
Frequently asked questions
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This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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