D-xylose吸收

定义

D-xylose吸收 is a laboratory test to check how well the intestines absorb a simple sugar (D-xylose). The test helps detect if nutrients are being properly absorbed.

选择的名字

Xylose tolerance test; Diarrhea - xylose; Malnutrition - xylose; Sprue - xylose; Celiac - xylose

如何执行测试

The test requires a blood and urine sample. 这些测试包括:

• 清洁捕获尿液样本
• 静脉穿刺(抽血)

There are several ways to perform this test. A typical procedure is described below, but make sure you follow the specific instructions you are given.

You will be asked to drink 8 ounces (240 ml) of water that contains 5 teaspoons (25 grams) of a sugar called d-xylose. The amount of d-xylose that comes out in your urine over the next 5 hours will be measured. You may have a blood sample collected at 1 and 3 hours after drinking the liquid. In some cases, the sample may be collected every hour. The amount of urine you produce over a 5-hour period is also checked. Your health care provider will tell you how to collect all of the urine during a 5-hour period.

How to Prepare for the Test

Do not eat or drink anything (even water) for 8 to 12 hours before the test. Your provider will ask you to rest during the test. A failure to restrict activity may affect test results.

Your provider may tell you to stop taking certain medicines that can affect test results. Medicines that can affect test results include aspirin, 阿托品, 吲哚美辛, 闷可乐, 和苯乙肼. DO NOT stop taking any medicine without first talking to your provider.

考试的感觉如何

When the needle is inserted to draw blood, 你可能会感到中度疼痛, or only a prick or stinging sensation. Afterward, there may be some throbbing.

Urine is collected as part of normal urination with no discomfort.

为什么要进行测试

Your provider may order this test if you have:

• 持续性腹泻
• 营养不良的迹象
• 不明原因的体重减轻

This test is primarily used to check if nutrient absorption problems are due to a disease of the intestines. It is performed much less often than in the past.

正常的结果

A normal result depends on how much D-xylose is given. In most cases, the test results are either positive or negative. A positive result means that D-xylose is found in the blood or urine and is therefore being absorbed by the intestines.

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

异常结果意味着什么

Lower than normal values may be seen in:

• 乳糜泻(口疮)
• 克罗恩病
• 贾第虫属 lamblia侵扰
• 钩虫 侵扰
• 淋巴阻塞
• 辐射肠病
• Small intestinal bacterial overgrowth
• 病毒性肠胃炎
• 惠普尔疾病

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:

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

注意事项

Multiple tests may be necessary to determine the reason for 吸收不良.

参考文献

Floch MH. Evaluation of the small bowel. 编辑:Floch MH. 网友的胃肠病学. 3日艾德. Philadelphia, PA: Elsevier; 2020:chap 62.

Semrad CE. Approach to the patient with diarrhea and 吸收不良. In: Goldman L, Schafer AI, eds. Goldman-Cecil医学. 26日艾德. Philadelphia, PA: Elsevier; 2020:chap 131.

Siddiqi HA, Rabinowitz S, Axiotis CA. Laboratory diagnosis of gastrointestinal and pancreatic disorders. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24日艾德. St Louis, MO: Elsevier; 2022:chap 23.