Xylose Absorption Test, Blood & Urine (Adult 25 g dose)

Abbrev Code:ARMISC   
Order Code:LAB4909Order Name:Send Out Misc Test
Order Instructions:Order LSMISC code one time only for blood and urine. Label clearly as fasting blood, 2 hour blood and 5 hour urine. Order UACOLL for volume documentation.
Synonyms:d-Xylose Absorption Test, Blood (25 g dose)
CPT Codes: 84620 x1
Turnaround Time:Specimens are sent to reference laboratory Mon-Sat; results are reported in 1-10 days.
Special Instructions:Record Xylose dose on request form. Urine specimen (5 hour collection) must be received with plasma to perform test. D-Xylose is available through the inpatient pharmacy.

This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.

Associated Links:

Urine Collection Procedure

Collection Instructions

Specimen:Blood and urine
Optimal Volume:4 mL blood; 10 mL urine
Minimum\Peds Volume:1.2 mL blood; 0.5 mL urine
Container:Gray (sodium fluoride + potassium oxalate), 3 L plastic jug
Collection Instructions:
  • The patient should fast for 8 hours prior to starting test.
  • Just prior to start of test, the patient should empty his or her bladder (DO NOT collect this urine).
  • Just prior to start of test, collect 4 mL (1.2 mL minimum) in gray (sodium fluoride + potassium oxalate) tube. Label this sample as "FASTING Plamsa". Send to lab immediately.
  • Give adults 25 g D-xylose (available through inpatient pharmacy) in 250 mL water. Encourage the patient to drink an additional 250 mL of water following the xylose dose. The patient may have water as desired, but no other food or fluids. Smoking should be prohibited. The patient should rest in a chair or on a bed until completion of test. Mild diarrhea is common following xylose ingestion.
  • Collect 4 mL (1.2 mL minimum) in gray (sodium fluoride + potassium oxalate) tube 2 hours after giving the xylose dose. Label this sample as "2-HOUR Plasma". Send to lab immediately.
  • After giving the xylose dose, collect all urine for the next 5 hours. Label this sample as "5-HR URINE".
Causes for Rejection:Plasma specimen not kept chilled; patient vomits test meal; loss of part of urine specimen and/or contaminated with stool.

Processing and Shipping

Specimen Processing:Centrifuge (FASTING and 2 hour blood samples) ASAP and aliquot 2 mL, 0.5 mL minimum. Measure and record total urine volume. Aliquot 10 mL urine, 0.5 mL minimum. Store in refrigerator. Record dose, urine volume and duration on request form.
Shipping Instructions:Ship at refrigerated temperature.
Stability:Plasma can be refrigerated indefinitely. Urine is stable for 14 days at room temperature, refrigerated or frozen.
Test Performed at or Referral Lab Lab Sendouts  (LabCorp via ARUP)
Referral Lab number:293837


Reference Range:
Plasma, 2 hours 32-58 mg/dL
Urine, Adults 65 years or younger >4.0 g/5 hours
Urine, Adults older than 65 years >3.5 g/5 hours
Use:Evaluate possible enterogenous malabsorption syndromes; test for functional integrity of the jejunum.

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