The vitamin A test measures the level of vitamin A in the blood.
How the Test is Performed
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. Afterwards, there may be some throbbing or slight bruising. This soon goes 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 20 to 60 micrograms per deciliter (mcg/dL) or 0.69 to 2.09 micromoles per liter (micromol/L).
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:
- Bones or teeth that do not develop correctly
- Dry or inflamed eyes
- Feeling more irritable
- Hair loss
- Loss of appetite
- Recurring infections
- Skin rashes
A higher than normal value means you have excess vitamin A in your blood (toxic levels). This may cause:
- Bone and muscle pain
- Double vision
- Hair loss
- Increased pressure in the brain (pseudotumor cerebri)
- Lack of muscle coordination (ataxia)
- Liver and spleen enlargement
- Loss of appetite
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
- Pancreas problems, such as swelling and inflammation (
pancreatitis) or the organ not producing enough enzymes (pancreatic insufficiency)
- Small intestine disorder called
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Multiple punctures to locate veins
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Ross AC. Vitamin A deficiencies and excess. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 61.
Salwen MJ. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 26.
Review Date: 29/09/2019
The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright ©2019 A.D.A.M., Inc., as modified by University of California San Francisco. Any duplication or distribution of the information contained herein is strictly prohibited.
Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Health. Please discuss with your doctor any questions or concerns you may have.