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Diagnosis of Helicobacter pylori: Improving the Sensitivity of CLOtest by Increasing the Number of Gastric Antral Biopsies

Siddique, Iqbal MBBS* †; Al-Mekhaizeem, Khalid MBBCh, FRCPC; Alateeqi, Nabeel MBBCh, FRCPC; Memon, Anjum MBBS, DPhil; Hasan, Fuad MBBCh, FACP* †

Journal of Clinical Gastroenterology: April 2008 - Volume 42 - Issue 4 - p 356-360
doi: 10.1097/MCG.0b013e31802b650d
ALIMENTARY TRACT: Clinical Research

Background and Goal The rapid urease CLOtest is commonly used during endoscopy to diagnose the presence of Helicobacter pylori. The aim of this study was to determine whether the sensitivity of the CLOtest can be improved by increasing the number of gastric antral biopsies from 1 to 4.

Methods The study included 100 adult patients who were referred for upper gastrointestinal endoscopy and tested positive for H. pylori infection on 13C urea breath test (“gold standard”). These 100 patients were then randomly divided into 4 equal groups (groups 1 to 4), and underwent an upper gastrointestinal endoscopy. Patients in group 1 had 1 gastric antral biopsy during endoscopy, whereas those in groups 2, 3, and 4 had 2, 3, and 4 biopsies, respectively. The biopsies were placed in the rapid urease CLOtests, which were incubated at room temperature for up to 24 hours, and read for positive results at 1, 6, and 24 hours.

Results About half of the patients (52%) had a positive CLOtest in group 1, compared to 68% in group 2, 76% in group 3, and 96% in group 4 (group 1 vs. 4 P<0.01). After 1 hour of incubation 96% of the patients in group 4 had a positive CLOtest, compared to 40% in group 3, 12% in group 2, and 4% in group 1.

Conclusions Increasing the number of gastric antral biopsies from 1 to 4 significantly improves the sensitivity of the CLOtest, eliminates sampling error, and hastens the time needed by the test to become positive for the diagnosis of H. pylori infection.

*Department of Medicine, Faculty of Medicine, Kuwait University, Safat, Kuwait

Thunayan Al-Ghanim Gastroenterology Center, Al-Amiri Hospital, Safat, Kuwait

Brighton and Sussex Medical School, Mayfield House, University of Brighton, Falmer, Brighton, UK

Preliminary results of this study were presented as a poster at the World Congress of Gastroenterology, Montreal, Canada, September 10–14, 2005.

The authors declare no conflict of interest.

The authors confirm that there is no financial arrangement with Ballard Medical Products, USA; KeyMed, UK; or SPSS Inc, USA.

Reprints: Dr Iqbal Siddique, MBBS, Department of Medicine, Faculty of Medicine, Kuwait University, P. O. Box 24923, Safat 13110, Kuwait (e-mail:

Received for publication September 4, 2006; accepted October 11, 2006

© 2008 Lippincott Williams & Wilkins, Inc.