Vitamin A measurement is used to check hypovitaminosis and toxic hypervitaminosis and to monitor supplement therapy.
Vitamin A (retinol) is a fat-soluble vitamin that is taken from foods of animal origin and from carotenes of plant-derived foods and stored in the liver. Vitamin A is absorbed by the intestine in the presence of bile and the enzyme lipase, is transported to the liver in the form of chylomicrons and stored in the liver as a retinol ester. Vitamin A is essential for the integrity of the mucous membranes, normal growth, and night vision. Vitamin A deficiency is more common in children of lower socioeconomic backgrounds.
Symptoms of acute toxic hypervitaminosis include long bone fragility and neurological changes similar to those observed at elevated intracranial pressure. Symptoms of chronic toxic hypervitaminosis include anemia, alopecia, ataxia, benign intracranial hypertension, brittle nails, cheilitis, conjunctivitis, diplopia, edema, erythema, rash, hepatitis, liver cirrhosis, hepatosplenomegaly, hyperostosis, neuritis (peripheral), swelling of the optic disc, petechiae, premature closure of the epiphyses, exfoliation of the skin.
Symptoms of vitamin A deficiency include changes in vision, including night vision loss, Bitot's spots, reduced growth, dry skin, and weak tooth enamel.
Possible Interpretations of Pathological Values
- Increase: Excessive intake of vitamin A supplements
- Decrease: Celiac disease, cystic fibrosis, infectious hepatitis, intestinal parasites, jaundice (obstructive), low levels of pre-albumin, malabsorption, nephritis (chronic), night vision loss, protein-calorie malnutrition. Vitamin A levels can be as much as 30% lower in the 3rd trimester of pregnancy.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. The correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.