Vitamin A (Retinol) Test
Vitamin A (Retinol) Test
Vitamin A is an essential nutrient that supports healthy vision, immune functions, bone formation, skin functions, and integrity. It helps maintain the lining of a mucous membrane and photoreceptors in the eyes. Deficiencies of vitamin A can cause night blindness and severe eye damage. Vitamin A in excess is toxic and it can lead to birth defects.
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The human body cannot produce vitamin A, and hence diet remains the main source of vitamin A. Animal products like meat, chicken liver, and cod liver oil contain vitamin A as retinol, and vegetables and fruits contain carotene which can be further converted into vitamin A in the liver. Vitamin A is a fat-soluble vitamin and is stored in the liver. It gets mobilized in the peripheral tissues of the liver. Vitamin A is carried in the blood by retinol-binding protein (RBP). Therefore, the liver’s capacity to produce RBP and the condition of the liver also impact the vitamin A level at the time of testing.
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Vitamin A deficiency is a major health concern in developing nations due to a poor diet. In developed countries, it is seen in malabsorption disorders, alcoholism, and liver disorders. Overuse of vitamin supplements can cause vitamin A toxicity.
Symptoms of vitamin A deficiency
Night blindness
Dry eyes
Corneal ulcerations
Skin Rash
Impaired immunity and recurrent infections
Growth retardation in children
Symptoms of vitamin A toxicity
Nausea and vomiting
Increased pressure on the brain
Abdominal pain
Swelling of bone, bone pain
Irritability
Blurry vision
Dizziness
Who should get tested?
This test is indicated in people having the following symptoms
Night blindness
Dry eyes
Dry scaly skin
Hair loss
Frequent infections
Growth retardation in children
Test preparation
A fasting blood sample is taken. Alcohol should not be consumed in the last 24 hours before sample collection. A blood sample is collected by inserting a needle into the vein in the arm.
Interpretation of the test results
The test result will show whether you have a deficiency or excess vitamin A. The normal range of retinol in blood is 20 to 60 mcg/dL. A lower-than-normal level range means that you are deficient and will need supplementation. A higher number than normal means that you have excess vitamin A and it is time to stop taking supplements as vitamin A toxicity can be harmful and sometimes fatal.
FAQs
Why do I need to take a vitamin A test?
The main reasons to get a vitamin A level test are to find if someone has a deficiency or excess of retinol in their blood and to monitor vitamin A therapy in those taking supplements.
What does an abnormal test report mean?
The abnormal test report may show either deficiency or excess vitamin A.
Can vitamin A levels be tested at home?
Vitamin A levels cannot be accurately measured at home. This requires a hospital setting and a lab.
Why does taking excess vitamin A supplements cause toxicity?
Vitamin A is a fat-soluble vitamin and excess can be stored in the liver. Therefore, it is advised not to overdo vitamin A supplementation.
What are the causes of vitamin A toxicity?
Causes of vitamin A toxicity include overconsumption of liver, excessive vitamin A supplementation, and long-term isotretinoin treatment for acne.
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