Vitamin A (Retinol), Serum

Vitamin A test is used to diagnose vitamin A deficiency or toxicity. Vitamin A deficiency presents with symptoms like night blindness and is seen with impaired intestinal absorption associated diseases. Vitamin A is a fat soluble vitamin, essential for normal vision, skin growth and integrity, bone formation, immune function. Vitamin A includes retinol, retinal, retinoic acid, and several provitamin A carotenoids (mostly beta-carotene). The body cannot synthesise vitamin A and must be supplied through diet. The sources of vitamin A are meat (retinol), vegetable and fruits (carotene). Deficiencies in vitamin A causes impaired night vision, eye damage, and blindness in severe cases. Vitamin A deficiency can be a primary or a secondary deficiency. A primary deficiency is seen in children and adults who do not consume provitamin A carotenoids present in fruits and vegetables adequately or preformed vitamin A present in animal and dairy products. Early weaning also increases the risk of vitamin A deficiency. Secondary vitamin A deficiency is associated with malabsorption of lipids, impaired production and release of bile, and exposure to oxidants (cigarette smoke, and chronic alcoholism). Vitamin A toxicity causes vision changes, bone pains and skin changes. Chronic toxicity can cause liver damage and increased pressure on the brain.