Poster (15W114)

H.pylori – It’s a bugs life!

Author(s)

J Doherty, K Sheahan, M Buckley

Department(s)/Institutions

Department of Gastroenterology, St Michaels Hospital, Dunlaoighre

Introduction

Helicobacter Pylori(HP) is a well-recognised cause of gastritis, PUD, gastric cancer, MALT lymphoma and is implicated in a subset of patients with dyspepsia. Recent recommendations are to 'Test and Treat' patients under 55years with 'non-worrying' upper GI symptoms. The Kyoto consensus paper recommended eradication of HP as first line treatment when found in association with gastritis and in HP positive patients with dyspepsia. There was 100% agreement that all patients treated should be followed up to assess cure rate. This has implications for service workload. This study compares three modalities of HP assay- (a)Carbon- Urease Breath Test(CUBT), (b)Rapid Urease Test(RUT) and (c)Histological examination.

Aims/Background

HP is estimated to colonise at least 50% of the world's population. CUBT is available in our hospital and a retrospective analysis of referrals for CUBT over 12months revealed a prevalence of 22.74%. Many units do not have access to CUBT and rely on RUT. Anecdotally in our unit we felt our yield from RUT(‘Quicktest’) to be lower than 20% and decided to compare histological assay with RUT. We also audited all CUBT referrals for the same period.

Method

We analysed 12 months data from 01/04/14-31/03/15. 488 patients had a CUBT. 247 patients who underwent an OGD and had a RUT performed were included. Each RUT included a specimen from antrum and corpus. Of these, 235 had biopsies from antrum and corpus for histological examination. Histology was considered gold standard and sensitivity, specificity, PPV and NPV of the RUT were compared to this.

Results

In the CUBT group there were 160 males and 328 females. Median age was 41(15-89 years). CUBT was positive in 22.74%(111/488) and negative in 77.26%(377/488) In the OGD group there were 86 males and 149 females. Median age was 51(16-96 years). RUT was positive in 11.49%(27/235) and negative in 88.51%(208/235). Histopathology detected HP in 15.32%(36/235) and did not in 84.68%(199/235). The sensitivity for RUT was 50%, specificity 95.48%, PPV 66.67% and NPV 91.35%.

Conclusions

Despite the RUT being faster and cheaper than sending biopsies, the sensitivity was significantly inferior to histology. In this study, despite sampling corpus and antrum, which should increase the yield of positive tests, 25% of HP positive patients were not diagnosed by RUT alone. A previous study demonstrated an almost 25% lower yield from Quicktest compared to Clotest. Taking biopsy samples entering the stomach rather than on exit and ensuring two samples are taken, from both corpus and antrum may increase the yield. If HP is suspected and RUT is negative, referral for CUBT should be considered.