Vitamin A blood test
The vitamin A test measures the level of vitamin A in the blood.
How the Test is Performed
A blood sample is needed.
How to Prepare for the Test
Follow your health care provider's instructions about not eating or drinking anything for up to 24 hours before the test.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or slight bruising. These soon go away.
Why the Test is Performed
This test is done to check if you have too much or too little vitamin A in your blood. (These conditions are uncommon in the United States.)
Normal values range from 50 to 200 micrograms per deciliter.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
A lower than normal value means you do not have enough vitamin A in your blood. This may cause:
- Bone or teeth problems in young children
- Dry or inflamed eyes
- Hair loss
- Loss of appetite
- Night blindness
- Recurring infections
- Skin rashes
Vitamin A deficiency may occur if your body has trouble absorbing fats through the digestive tract. This may occur if you have:
- Chronic lung disease called cystic fibrosis
- Pancreas problems, such as swelling and inflammation (pancreatitis) or the organ not producing enough enzymes (pancreatic insufficiency)
- Small intestine disorder called celiac disease
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 225.
Salwen MJ. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 26.