The Vitamin A test measures the level of this essential nutrient, which is critical for healthy vision, a strong immune system, and skin health. This test is vital if you are experiencing symptoms of deficiency, such as night blindness, dry skin, or frequent infections. It is also used to monitor for vitamin toxicity in those taking high-dose supplements. A simple blood draw provides a clear picture of your body's Vitamin A status, ensuring this key nutrient is in the optimal range to protect your vision and immunity.