A Vitamin C blood test measures the levels of vitamin C in the blood. Vitamin C, also known as ascorbic acid, is a nutrient that is important for the formation of collagen, the maintenance of healthy skin and connective tissue, and the absorption of iron. It is also an antioxidant, which means it helps protect the body's cells from oxidative stress. Vitamin C is found in a wide variety of foods, including citrus fruits, berries, and leafy green vegetables, and is also available as a dietary supplement.

The results of a Vitamin C blood test can help a healthcare provider diagnose and monitor conditions related to vitamin C levels, such as vitamin C deficiency or excess, liver problems, and malnutrition. The test can also be used to monitor the effectiveness of vitamin C supplementation. Vitamin C deficiency, also known as scurvy, is rare in developed countries but can cause a wide range of symptoms, including fatigue, weakness, muscle pain, and skin problems. It is important to treat vitamin C deficiency promptly to prevent these complications.