D-xylose absorption rate (2-hour urine test)
This test measures how well your body absorbs D-xylose, a simple sugar, over two hours. It helps assess intestinal function, particularly in diagnosing conditions like celiac disease or short bowel syndrome.
["This test checks gut absorption—key for diagnosing digestive disorders."]
Key facts at a glance
- LOINC
- 41191-8
- Short code
- Xylose 2h p Xyl PO 2h Ur-mRate
- Synonyms
- Xylose 2h p Xyl PO 2h Ur-mRate
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 20
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82670
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may recommend this test if you have symptoms like chronic diarrhea, weight loss, or unexplained nutrient deficiencies. It’s also used to evaluate malabsorption syndromes or to monitor gut health after surgery or disease.
How Is the Test Performed?
You’ll drink a solution containing D-xylose, then provide a urine sample every hour for two hours. The test measures how much sugar appears in your urine, reflecting how well your intestines absorbed it.
What Does the Result Mean?
A lower than expected absorption rate suggests poor intestinal function, which may indicate conditions like celiac disease, Crohn’s disease, or other digestive issues. Results are interpreted by your healthcare provider in context with your symptoms and medical history.
Common Conditions Linked to This Test
Abnormal results often point to malabsorption disorders, such as celiac disease (gluten-related intestinal damage), inflammatory bowel disease, or other gastrointestinal conditions that interfere with nutrient uptake.
Reference range
Premenopausal: 20-400 pg/mL; Postmenopausal: <30 pg/mLN/A
No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used to diagnose or evaluate intestinal absorption disorders. It provides objective evidence of how effectively your small intestine processes nutrients, guiding treatment decisions for conditions like chronic diarrhea, malnutrition, or post-surgery recovery.
Short name
D-Xylose Urine Rate
Frequently asked questions
What does a low or high absorption rate mean?
How long does it take to get results?
Can I eat or drink anything before the test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy