This test is requested to assess the absorption of xylose and carbohydrates in the intestine. For this purpose, a standard amount of Xylose is ingested in the laboratory and its content is then measured in the patient’s blood and urine.


48 hours before the test:

  • You may not take the following medication: aspirin, indomethacin, neomycin, digoxin, glizipide, kanamycin, opioids, MAOIs, nalidixic acid or opioids.
  • You may not eat bread, starches, baked goods, jelly or juice.
  • You may only eat meat, milk, dairy products and fish.


On the day of the test:

  • Fast for 12 hours (you may drink water).
  • The test must be taken in the morning.
  • Take your usual medication, except for the ones mentioned above, always in consultation with your doctor.


During the test:

  • Avoid all physical activity and remain seated.

5 hours.


The nurse will ask you to go to the toilet. This first urine is not collected, it is flushed down the toilet.

A blood draw will then be performed, followed by administration of a solution containing 25 grams of D-Xylose (0.5 g/kilo of weight in children, up to a maximum of 25 grams), and after 2 hours another blood draw will be performed.

From the time you take D-Xylose, and for the next 5 hours, you will drink 4 glasses of water. You will collect all the urine you pass in the bottles provided by the laboratory.

If vomiting occurs during the test, the test is interrupted and will be carried out on another day, and the test must be repeated from the beginning.

Tiempo de respuesta o Resultado: 

7 days.

Info adicional: 

If you have any further questions, please do not hesitate to contact Analiza by email at [email protected] or by telephone on 902 67 64 57 or 914 297 541