Vitamin A (Retinol) Test

The vitamin A (retinol) test measures the levels of vitamin A in the blood. Vitamin A is essential for healthy vision, immune function, and cell growth and differentiation.

The test may be ordered if a person is experiencing symptoms of vitamin A deficiency, such as night blindness, dry skin, or poor immune function. It may also be ordered to monitor the effectiveness of treatment for vitamin A deficiency.

To perform the test, a blood sample is typically taken from a vein in the arm. The sample is then sent to a laboratory for analysis. Results are usually reported as the amount of vitamin A in the blood in either micrograms per deciliter (mcg/dL) or micromoles per liter (umol/L).

Normal levels of vitamin A in the blood range from 20-80 mcg/dL or 0.7-3.0 umol/L. Levels below this range may indicate a deficiency, while levels above this range may indicate excess vitamin A intake, which can be toxic.