Vitamin A blood test

定义

The vitamin A test measures the level of vitamin A in the blood.

选择的名字

视黄醇测试

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. 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.)

正常的结果

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. 这可能导致:

• Bones or teeth that do not develop correctly
• Dry or inflamed eyes
• Feeling more irritable
• 脱发
• 食欲不振
• 夜盲症
• Recurring infections
• 皮疹

A higher than normal value means you have excess vitamin A in your blood (toxic levels). 这可能导致:

• 贫血
• Bone and muscle pain
• 腹泻
• 复视
• 脱发
• Increased pressure in the brain (pseudotumor cerebri)
• Lack of muscle coordination (ataxia)
• Liver and spleen enlargement
• 食欲不振
• 恶心想吐

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 囊性纤维化
• Pancreas problems, such as swelling and inflammation (胰腺炎) or the organ not producing enough enzymes (pancreatic insufficiency)
• Small intestine disorders that reduce nutrient absorption, such as 乳糜泻

风险

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
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

参考文献

Markell M, Siddiqui HA. Vitamins and trace elements. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. Philadelphia, PA: Elsevier; 2022:chap 27.

罗斯交流. Vitamin A deficiencies and excess. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21艾德. Philadelphia, PA: Elsevier; 2020:chap 61.