Vitamin A is a fat-soluble vitamin that is derived from two sources: preformed retinoids and provitamin carotenoids. Retinoids, such as retinal and retinoic acid, are found in animal sources like liver, kidney, eggs, and dairy products. Carotenoids like beta-carotene (which has the highest vitamin A activity) are found in plants such as dark or yellow vegetables and carrots. Vitamin A acts as an antioxidant, and is required for normal vision (since it is required for the formation of rhodopsin), growth and differentiation of epithelial tissue as well as bone growth, immunity, reproduction and embryonic development. Vitamin A DEFICIENCY can result from inadequate intake, fat malabsorption, or liver disorders. Deficiency impairs immunity and hematopoiesis and causes skin rashes and typical ocular effects (eg, xerophthalmia, night blindness). Vitamin A TOXICITY can cause increased intracranial pressure, vertigo, diplopia, seizures, as well as cheilosis, glossitis, alopecia, bone pain, hyperlipidemia, and liver fibrosis.
Hemolyzed and lipemic samples are not accebtable. Protect from light