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Test Code LAB7041 CLO (H.Pylori Urease Screen)

Performing Laboratory

St. Louis Children's Hospital Laboratory - POC

Specimen Requirements

Specimen type: Tissue from gastric mucosal biopsy

Patient Preparation: Patient should discontinue the use of antibiotics and bismuth preparations three weeks before the biopsy.

Collection Container/Tube:

Preferred/Acceptable: CLOtest® cartridge

   WIth a clean applicator device (sterile needle) push the entire sample from the forceps beneath the surface of the gel. Send biopsy submitted in CLOtest® cartridge.

Specimen Collection Volume: 2-3 mm tissue

   NOTE: The recommended gastric area to biopsy is at least 2 cm away from the pylorus along the curve of the antrum.

Specimen collection instructions:

  1. Warm CLOtest® cartridge to room temperature 7-10 minutes before endoscopy.
  2. Inspect cartridge to make sure well is full and is a yellow color.
  3. Peel back the label of the CLOtest® cartridge. With a sterile needle, remove the specimen from the biopsy forceps and push the tissue into the CLOtest gel, making certain the tissue is completely immersed. Re-seal the CLOtest® cartridge and send to lab.

    NOTE: Excise tissue that appears normal, avoiding tissue that appears ulcerated.

Submission Container/Tube: If specimen is coming from outside facility send CLOtest® cartridge in biohazard bag at ambient temperature.

Special Instructions: Send to lab promptly

Sample Rejection

Mislabled or unlabeled specimens

Logistics

Test set up: Monday-Friday

Cut-off time: None, cartridges are read mid afternoon

Turnaround Time: 24-72 hours

Reference Values

Reference Interval: Report as: Negative or Positive

Critical Value: None established

Methodology

CLOtest Rapid Urease test

Limitations

  • Possible causes of False Negatives:

    • Very low numbers of H. pylori in the tissue sample

    • Patchy H. pylori distribution so that the organism is not captured in the tissue sample

    • A sample of intestinal metaplasia—H. pylori does not colonize intestinal mucosa

    • Recent ingestion of antibiotics, bismuth, proton pump inhibitors, or sucralfate which can inhibit the organism

    • Formalin contamination of the sample

  • Possible causes for False Positives:

    • Patients who have achlorhydria from bacterial overgrowth could exhibit false positives. This condition could result from the following: pernicious anemia, previous gastric surgery, or recent use of proton pump inhibitor drugs. However, other bacteria produce much less urease than H. pylori and should not cause a rapid color change.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: No processing. Log the specimen into "SLC Decent" in LIS then place cartridge in wire basket in processing area labeled "CLOtest".

Processed Volume: NA

Transport/Storage Temperature: Ambient

 

Analyte Stability:

Specimen Type Temperature Time    
CLOtest cartridge     Ambient NA
  Refrigerated     NA  
  Frozen  NA   

Test Classification and CPT Code

87007

LOINC

NA

Last Reviewed

08/2025