D-xylose absorption test (24-hour urine collection)
This test measures how well your body absorbs and uses the sugar D-xylose, which helps assess intestinal function and malabsorption disorders.
["Helps diagnose conditions affecting nutrient absorption in your intestines."]
Key facts at a glance
- LOINC
- 22624-1
- Short code
- Xylose 2h p 5 g Xyl PO Bld-sCnc
- Synonyms
- Xylose 2h p 5 g Xyl PO Bld-sCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 20
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82670
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order this test if you have symptoms like chronic diarrhea, weight loss, or unexplained nutrient deficiencies, or if they suspect conditions like celiac disease, short bowel syndrome, or other intestinal malabsorption issues.
What to Expect Before the Test
You’ll need to collect your urine for 24 hours, starting after an overnight fast. Your doctor or lab technician will provide detailed instructions on proper collection and handling to ensure accurate results.
How the Test Works
After fasting overnight, you’ll drink a solution containing D-xylose. Your urine is then collected for 24 hours. The test measures the amount of D-xylose excreted in your urine, reflecting how well your intestines absorbed it.
What the Results Mean
Lower than expected levels of D-xylose in urine suggest poor absorption, which may indicate intestinal issues. Results are interpreted in relation to your symptoms and other tests.
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.
Clinical Significance: This test is primarily used to identify intestinal malabsorption disorders, such as celiac disease, tropical sprue, or other conditions that impair nutrient uptake. It can help guide treatment decisions, such as dietary changes or medical interventions.
Short name
D-Xylose Urine Test
Frequently asked questions
What does a low result 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