D-Xylose Absorption Test (24-Hour Urine Collection)
This test measures how well your body absorbs the sugar D-xylose, which helps assess intestinal function and malabsorption disorders.
["A low absorption rate may indicate problems like celiac disease or short bowel syndrome."]
Key facts at a glance
- LOINC
- 41257-7
- Short code
- Xylose 2h p 25 g Xyl PO Ur-mCnc
- Synonyms
- Xylose 2h p 25 g Xyl PO Ur-mCnc
- 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, or if you have a suspected condition affecting how your intestines absorb nutrients.
What to Expect Before the Test
You’ll need to collect your urine for 24 hours after drinking a specific dose of D-xylose. Follow your healthcare provider’s instructions carefully to ensure accurate results.
How the Test Works
After drinking the D-xylose solution, your body absorbs some of it through the intestines. The test measures how much xylose appears in your urine over 24 hours to determine absorption efficiency.
What the Results Mean
Results are typically compared to a standard absorption rate. Lower than expected levels may suggest malabsorption, while normal results indicate healthy intestinal function.
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 particularly useful for diagnosing conditions like celiac disease, tropical sprue, or other intestinal disorders that interfere with nutrient absorption. It can also help rule out conditions where dietary changes might be needed.
Short name
D-Xylose Test
Frequently asked questions
What is the normal range for this test?
How long does it take to get results from this test?
Can I eat or drink anything before the D-xylose 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