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d-Xylose Absorption Test, Urine
Test Code941
CPT Codes
84620
Preferred Specimen
5 mL 5-hour urine in a plastic leak-proof container
Patient Preparation
Adult patients and children should be kept fasting overnight and during test period (infants are fasted for 4 hours)
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.
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.
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
A.M. Sets up 2 days a week.
Report Available
Reports same day.
Clinical Significance
The xylose absorption test is useful in screening for carbohydrate malabsorption.