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St. Louis, MO 63110
POC.1.0263. Page 1 of 5
PROCEDURE: CLO TEST
ISSUE DATE: October 2003 REVISION DATE: August 2005, October 2007, January 2010, July 2015, June 2017
REVIEW DATE: June 2018
Principle:
The CLOtest rapid urease test accurately and conveniently detects the urease enzyme of Helicobacter pylori in gastric mucosal biopsies. Its use is intended for the presumptive diagnosis of H. pylori infection.
H. pylori was first cultured from antral biopsies in 1982 and was originally called Campylobacter-like organism. Subsequently, the genus was named Helicobacter , meaning spiral or helical bacteria.
CLOtest is a well of urease indicator gel sealed inside a plastic slide. The gel contains urea, phenol red, buffers and a bacteriostatic agent to prevent the growth of contaminating urease-positive organisms. If the urease from H. pylori is present in the tissue sample, it changes the gel from yellow to bright magenta.
Specimen:
Specimens are collected in the Ambulatory Procedure Center, SDS, OR or the CSCC. The recommended gastric area to biopsy is at least 2 cm away from the pylorus along the lesser or greater curve of the antrum. Tissue should be excised that appears normal. Avoid tissue that is eroded or ulcerated as H. pylori may be present in smaller numbers around those areas. The patient should discontinue the use of antibiotics and bismuth preparations three weeks before the biopsy. These agents may suppress but not eradicate the presence of H. pylori making the organism difficult to detect by any means.
Materials:
2-3mm tissue sample obtained by endoscopist CLOtest device stored at 2 - 8°C CLOtest Reagent Urease Type III Forceps
St. Louis, MO 63110
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Quality Control:
Quality control must be performed on all new shipments and new lot numbers of the CLOtest. The lot number, expiration date and QC results will be documented on the CLO test Quality Control form in the Microbiology Lab. Two slides are removed from the package and allowed to come to room temperature. Inoculate one gel with one capsule of the CLOtest Reagent Urease Type III and leave the other gel uninoculated to serve as the negative control. Incubate at room temperature for 24 hours. Interpret and record results after 24 hours.
CLOtest Reagent Urease Type III =
POSITIVE
(red to magenta color)
Uninoculated =NEGATIVE
(yellow)
If expected results are not obtained, notified Technical Supervisor or designee.
Procedure:
Ambulatory Procedure Center/SDS/OR/CSCC
- Before use, the CLOtest should be inspected to make sure that the well is full and is a yellow color.
- Immediately before endoscopy, the CLOtest should be warmed to room temperature 7- minutes.
- Peel back the label of the CLOtest exposing the gel.
- With a sterile needle, remove the specimen from the biopsy forceps and push the tissue into the CLOtest gel. Make certain the tissue is completely immersed so that there is maximum contact with the gel.
- Reseal the CLOtest. Record or use the label, identification must include the name of the patient, DOB and account number and the date and time specimen was inserted on the CLOtest slide.
- Send the device to the lab.
St. Louis, MO 63110
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- If the gel does not turn red or magenta, notify the Supervisor or Technical Specialist immediately. Do not report patient results.
- If the gel does turn red or magenta, the fail-safe protocol has been verified and the CLOtest is working properly. In the work card portion of CERNER, enter the biochemical ‘CLOVER’— “Fail-safe protocol confirms this negative test to be working properly.”
- Specimens are stored refrigerated for 7 days.
Reporting:
Results are entered into Accession Result Entry.
Enter FINAL into the ENTRY box. Enter POSITIVE or NEGATIVE into the response box and verify.
Limitations of the Test:
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.
St. Louis, MO 63110
POC.1.0263. Page 5 of 5
References:
CLOtest Rapid Urease Test package insert. Halyard Health Inc. 2015
Written By: Revised By: Donna Walck
________________________________________________ _______________________
Laboratory Medical Director and Microbiology Date Medical Director
________________________________________________ _______________________
Technical Supervisor Date
Annual Review: Medical Director/Designee Date
________________________________________________ _______________________
________________________________________________ _______________________
________________________________________________ _______________________
________________________________________________ _______________________
Location of hard copy location(s): SLC Core lab
Date Archived: _______________________
