Understanding the marker
The test measures serum retinol, a form of vitamin A. Its concentration is not a direct measure of dietary intake or body stores.
The test measures retinol in blood for specific questions about vitamin A supply. It does not directly measure body stores or intake, and inflammation can lower it. Vitamin A supplements need careful review because excess intake can be harmful; advice depends on the product, dose and individual circumstances.
What does high Vitamin A (Retinol) mean?
A high retinol result needs assessment of the actual level and possible vitamin A exposure, including supplements if used. Excess intake can be harmful. A clinician can assess the product, dose and personal circumstances before advising on next steps.
What does low Vitamin A (Retinol) mean?
A low retinol result is assessed with symptoms, intake, absorption and inflammation. It does not directly quantify vitamin A stores or establish the cause of a symptom.
More markers in the same area
- Vitamin D (25-OH)the blood measure used to assess vitamin D supply
- Vitamin B12needed for nerves and red cells
- Folate (B9)helps your body make new cells
- Vitamin E (alpha-Tocopherol)a vitamin that helps protect cell membranes
- Holotranscobalaminthe portion of B12 available for cells to take up
- MagnesiumFor muscle and nerve function
This is general information about the marker, not an assessment of your values and not medical advice. Last updated: October 2026.