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d-Xylose Absorption Test, Urine [941X]
MessageOrder Misc Quest Test Code 941X.
Test Code
d-Xylose Absorption Test, Urine
Quest Code
11613
CPT Codes
84620
Preferred Specimen
5 mL of a 5-hour fasting urine submitted in a fluoride oxalate (gray-top) tube
Patient Preparation
Patient must fast for 8 hours (except for water) prior to administration of d-Xylose. Pediatrics patients must fast for at least 4 hours. No food is permitted during the test, only water. Patients should refrain from eating foods containing fruits, jams, jellies and pastries and avoid taking medications including aspirin, indomethacin, other nonsteroidal anti-inflammatory drugs, neomycin, glipizide or atopine which interfere with the test results. These should be discontinued for 24 hours prior to the test. No water restriction is required, in fact, patients are encouraged to drink water during the fasting period and during the test.
Minimum Volume
1 mL
Instructions
Note: This test cannot be performed at a Patient Service Center because of the preparation step required for the d-Xylose solution.
1.) At the start of the test, have the patient empty the bladder completely and discard the urine. Some physicians recommend checking a fasting urine and/or a blood sample for non-specific interferences. If requested, retain an aliquot of the urine and collect a blood specimen at this time.
2.) Give 25 grams of D(+)-xylose (or 5 grams if so specified by the physician) dissolved in 250 mL water followed immediately by an additional 250 mL water to ensure a urine flow of at least 60 mL/hour. For children, give 0.5 g xylose/kg of body weight up to 25 g, reducing the amount of water accordingly.
3.) Collect all urine specimens voided during the next 5-hour period, including the final 5-hour void in the same container. Keep container refrigerated during collection.
4.) Mix total urine collection thoroughly, measure total volume and aliquot. Aliquot urine into an empty (gray-top) blood collection tube (the oxalate/fluoride will serve as a preservative for the urine). If (gray-top) tube is glass, please transfer urine to a plastic tube before shipping.
5.) Record the dose of Xylose given and the total 5-hour volume of the urine collection.
If additional tests are ordered, please submit a separate specimen.
Adult patients and children should be kept fasting overnight and during test period (infants are fasted for 4 hours).
OK to thaw.
1.) At the start of the test, have the patient empty the bladder completely and discard the urine. Some physicians recommend checking a fasting urine and/or a blood sample for non-specific interferences. If requested, retain an aliquot of the urine and collect a blood specimen at this time.
2.) Give 25 grams of D(+)-xylose (or 5 grams if so specified by the physician) dissolved in 250 mL water followed immediately by an additional 250 mL water to ensure a urine flow of at least 60 mL/hour. For children, give 0.5 g xylose/kg of body weight up to 25 g, reducing the amount of water accordingly.
3.) Collect all urine specimens voided during the next 5-hour period, including the final 5-hour void in the same container. Keep container refrigerated during collection.
4.) Mix total urine collection thoroughly, measure total volume and aliquot. Aliquot urine into an empty (gray-top) blood collection tube (the oxalate/fluoride will serve as a preservative for the urine). If (gray-top) tube is glass, please transfer urine to a plastic tube before shipping.
5.) Record the dose of Xylose given and the total 5-hour volume of the urine collection.
If additional tests are ordered, please submit a separate specimen.
Adult patients and children should be kept fasting overnight and during test period (infants are fasted for 4 hours).
OK to thaw.
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 30 days
Refrigerated: 7 days
Frozen: 30 days
Methodology
Colorimetric (C)
Setup Schedule
Set up: Mon, Thurs; Report available: 1-3 days
Reference Range
| 25 g dose | 4.1-8.2 g in 5-hour urine | |
| 5 g dose | 1.2-2.4 g in 5-hour urine | |
Clinical Significance
The xylose absorption test is useful in screening for carbohydrate malabsorption.
Performing Laboratory
| Quest Diagnostics Nichols Institute |
| 14225 Newbrook Drive |
| Chantilly, VA 20153 |
Last Updated: September 10, 2019
