D-xylose absorption test (2-hour serum concentration)
This test measures how well your body absorbs the sugar D-xylose, which helps assess intestinal function and malabsorption disorders.
["Checks if your intestines are absorbing nutrients properly."]
Key facts at a glance
- LOINC
- 22625-8
- Short code
- Xylose 2h p Xyl PO Bld-sCnc
- Synonyms
- Xylose 2h p 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 This Test Is Done
Your doctor may recommend this test if you have symptoms like chronic diarrhea, unexplained weight loss, or signs of malabsorption (such as vitamin deficiencies). It can also be used to diagnose conditions like celiac disease, short bowel syndrome, or intestinal infections.
How the Test Works
You’ll drink a solution containing D-xylose, and your blood will be drawn 2 hours later to measure the amount of xylose in your serum. This helps determine how efficiently your intestines absorbed the sugar.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for a few hours before the test to ensure accurate results. Wear comfortable clothing and plan for a few hours to complete the process.
What to Expect During the Test
You’ll drink a sweet-tasting liquid containing D-xylose, and a blood sample will be taken 2 hours later. The process is quick and painless, similar to a routine blood draw.
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.
Low xylose levels in your blood after 2 hours suggest poor intestinal absorption, which may indicate malabsorption syndromes, inflammatory bowel disease, or other gastrointestinal issues. Normal results generally mean your intestines are functioning well.
Short name
D-Xylose Absorption Test
Frequently asked questions
What does a low result mean?
What does a high result mean?
How often is this test repeated?
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