Galactose-1-phosphate uridyltransferase blood test

定义

Galactose-1-phosphate uridyltransferase is a blood test that measures the level of a substance called GALT, which helps break down milk sugars in your body. A low level of this substance causes a condition called 半乳糖血症.

选择的名字

Galactosemia screen; GALT; Gal-1-PUT

How the Test is Performed

A 血液样本 是必要的.

How the Test will Feel

When the needle is inserted to draw blood, some infants feel moderate pain. Others feel only a prick or stinging. Afterward, there may be slight bruising. 这很快就会消失.

Why the Test is Performed

This is a screening test for 半乳糖血症.

In normal diets, most galactose comes from the breakdown (新陈代谢) of lactose, which is found in milk and dairy products. One out of 65,000 newborns lack a substance (enzyme) called GALT. Without this substance, the body cannot break down galactose, and the substance builds up in the blood. Continued use of milk products can lead to:

• Clouding of the lens of the eye (白内障)
• Scarring of the liver (肝硬化)
• 未能茁壮成长
• Yellow color of the skin or eyes (黄疸)
• 肝脏肿大
• Intellectual disability

This can be a serious condition if not treated.

Every state in the United States provides newborn screening tests to check for this disorder.

正常的结果

The normal range is 18.5 to 28.5 U/g Hb (units per gram of 血红蛋白).

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different samples. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

An abnormal result suggests 半乳糖血症. Further tests must be done to confirm the diagnosis.

If your child has 半乳糖血症, a genetics specialist should be consulted promptly. The child should be put on a no-milk diet right away. This means no breast milk and no animal milk. Soy milk and infant soy formulas are generally used as substitutes.

This test is very sensitive, so it does not miss many infants with 半乳糖血症. But, false-positives can occur. If your child has an abnormal screening result, follow-up tests must be done to confirm the result.

风险

There is little risk in taking blood from an infant. Veins and arteries vary in size from one infant to another and from one side of the body to the other. Obtaining a 血液样本 from some infants may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

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

参考文献

Chernecky CC, Berger BJ. Galactose-1-phosphate - blood. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6日艾德. St Louis, MO: Elsevier Saunders; 2013:550.

帕特森MC. Diseases associated with primary abnormalities in carbohydrate 新陈代谢. In: Swaiman KF, Ashwal S, Ferriero DM, et al, eds. Swaiman's Pediatric Neurology. 6日艾德. Philadelphia, PA: Elsevier; 2017:chap 39.