Vitamin A and carotene are essential nutrients that play critical roles in vision, immune function, cell growth, and development. This test measures both vitamin A (retinol) and beta-carotene levels in the blood. Vitamin A deficiency can cause night blindness, dry eyes, increased susceptibility to infections, and in severe cases, complete blindness. Beta-carotene is a provitamin that the body converts to vitamin A and also acts as an antioxidant. Low levels of both nutrients often indicate poor dietary intake or malabsorption disorders. This test is commonly ordered when evaluating patients with vision problems, frequent infections, or symptoms of malnutrition. It's particularly important for individuals with conditions that affect fat absorption, such as celiac disease, inflammatory bowel disease, or pancreatic disorders, as vitamin A requires fat for proper absorption.