Vitamin A

When there is no vitamin A in the food, the daily liver loss is about 0.5% of the total. Vitamin A is closely related to normal vision, which is necessary for normal bone growth, contributes to cell proliferation and growth, and is important for the normal formation, development and maintenance of epithelium. Vitamin A has the effect of delaying or preventing pre-lesions and preventing chemical carcinogens, especially preventing epithelial malignancies. Quantitative determination of serum vitamin A is of great significance for the diagnosis and treatment of certain diseases. Basic Information Specialist classification: growth and development check classification: biochemical examination Applicable gender: whether men and women apply fasting: fasting Analysis results: Below normal: Can be seen in vitamin A deficiency (night blindness, dry eye, corneal softening disease), lipid malabsorption syndrome, follicular keratosis, zinc deficiency, liver damage, obstructive jaundice, hyperthyroidism, trauma and so on. Normal value: Vitamin A (adult): 1.12-3.14μmol/L Vitamin A (child): 0.87-1.56μmol/L Vitamin A (premature baby newborn #?.52-0.78μmol/L Above normal: Can be seen in vitamin A excess, renal insufficiency, hypothyroidism. negative: Positive: Tips: Do not eat too greasy, high-protein foods the day before the blood draw, avoid heavy drinking. Normal value Fluorescence spectrophotometry Newborns in premature infants: 0.52 to 0.78 μmol/L. Children: 0.87 to 1.56 μmol/L. Adult: 1.12 to 3.14 μmol/L. Clinical significance Abnormal results: 1, reduction: vitamin A deficiency (night blindness, dry eye, corneal softening disease), lipid malabsorption syndrome, follicular keratosis, zinc deficiency, liver damage, obstructive jaundice, hyperthyroidism, trauma Wait. 2, elevated: vitamin A excess, renal insufficiency, hypothyroidism. Low results may be diseases: vitamin A deficiency in children, external hydrocephalus in children, cystic fibrosis, chronic gastritis, malabsorption of sugar in children, excessive vitamin A, excessive intake of vitamin A, red pityriasis, Nutritional metabolic disorders, vitamin A poisoning results may be high disease: dystrophic edema in children, vitamin A deficiency neurological considerations Inappropriate people: generally no special population. Forbidden before examination: Please inform the doctor about the recent medication and special physiological changes before the test. 1, do not eat too greasy, high-protein food the day before the blood, to avoid heavy drinking. The alcohol content in the blood directly affects the test results. 2. After 8 pm on the day before the medical examination, you should start fasting for 12 hours to avoid affecting the test results. Requirements for examination: When taking blood, you should relax your mind, avoid the contraction of blood vessels caused by fear, and increase the difficulty of blood collection. Inspection process Immediately after the collection of venous blood, the test is performed: 1. Pipette 4.0ml of petroleum ether extract after determination of β-carotene in a dry cuvette, place it in a drying tube, place it in a 50°C water bath, carefully blow dry carbon dioxide gas, and do not extract petroleum ether. Spill out until completely dry (no odor). 2. Immediately add 0.5 ml of chloroform to the residue to prevent oxidation damage of vitamin A. 3. Remove the cuvette and add 1 drop of acetic anhydride to mix to prevent possible moisture and turbidity of the coloring solution. Not suitable for the crowd It is necessary to check the population for the group related to the above-mentioned diseases, and other people do not need to be tested. Adverse reactions and risks complication: 1, long-term use of large doses, there will be anorexia, diarrhea, hyperesthesia, eyeballs, blood, prothrombin deficiency and vitamin C metabolism disorders. 2, infants and young children caused by false brain tumor signs, tinnitus, bulging bulging, cerebrospinal fluid pressure, exfoliative dermatitis, bone hypertrophy, dry sputum cup-shaped concave, anti-A and so on. 3, liver dysfunction often accompanied by hepatosplenomegaly, increased blood calcium and ascites. 4, children, adults can cause dry skin and mucous membranes and aplastic anemia. harm: Vitamin A promotes growth and development, prolongs life and protects vision and epithelial cells. Its role is especially important for children. Vitamin A deficiency, growth stagnation, night blindness, dry eye disease and other diseases. However, excessive vitamin A can also cause symptoms of poisoning: long-term application of large doses can cause hypervitaminosis A, and even acute or chronic poisoning, the highest incidence of infants from 6 months to 3 years old. It is characterized by loss of appetite, itchy skin, dry hair, hair loss, cleft palate, irritability, bone pain, fracture, increased intracranial pressure (headache, vomiting, anterior iliac crest and bulge), disappear after 1 to 2 weeks of withdrawal. . Adults with more than 1 million units in one dose and more than 300,000 units in a child can cause acute poisoning. Regardless of adults or children, such as continuous daily serving 100,000 units for more than 6 months, can cause chronic poisoning, need to pay attention.

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