1-5 days after setup at PeaceHealth Laboratories’ reference lab.
CPT Code:
84620-90
Specimen Collection Details
Collection:
Patient to fast eight hours (minimum four hours) prior to start of test. BEFORE D-XYLOSE DOSAGE: Just prior to test patient should empty bladder. DO NOT collect this urine. Collect first serum sample using one 7.5 mL serum separator tube (SST) (Min: 0.5 mL). Label this specimen “Fasting Serum.” ADMINISTER D-XYLOSE (25 g Dose): Give adults 25g D-Xylose dissolved in 250 mL water. Encourage patient to drink an additional 250 mL water. Patient may have water as desired, but no other fluids or food. Smoking is prohibited. Patient should rest in chair or bed until completion of test. Mild diarrhea is common following xylose ingestion. POST-DOSAGE OF D-XYLOSE: Begin five-hour urine collection. Collect ALL urine for next five hours. Refrigerate during and after collection. TWO HOURS POST-DOSAGE OF D-XYLOSE: Collect second serum sample (Min: 0.5 mL). Label this specimen “Two-Hour Serum.” For patients who do not tolerate the 25g xylose dose, a 5g dose can be used. Refer to Xylose, Absorption, Adult 5g (90845).
Handling:
SERUM: Allow serum to clot completely at ambient temperature. Centrifuge, separate serum from cells as soon as possible, and pour into a plastic vial. Refrigerate. Label specimens appropriately as “Fasting Serum” and “Two-Hour Serum.” URINE: Measure and record the volume, mix well, and remove a 5 ml aliquot. Label this specimen as “Five-Hour Urine.” Entire five-hour collection may be submitted to lab for measuring and aliquoting. Record the total volume and the D-Xylose dose given on both the urine aliquot tube AND on the requisition form. Failure to include required information will result in delayed turnaround time.
Stability:
4 hours ambient, 7 days refrigerated, or 1 month frozen.
Standard Volume:
1 mL serum each (fasting and two-hour) draw, and 5 mL urine.
Minimum Volume:
0.5 mL serum each (fasting and two-hour) draw, and 3 mL urine.
Transport:
Refrigerated.
Rejection Criteria:
Gross hemolysis; whole blood or unspun clot tubes; non-fasting specimen.
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