title: Comparison of the 13C-urea breath test and the endoscopic phenol red mucosal pH test in the quantification of Helicobacter pylori infection loading.
abstract: OBJECTIVE
  The (13)C-urea breath test (UBT) is a semiquantitative test for measuring Helicobacter pylori infection loading. H. pylori produces ammonia, which elevates the pH of the gastric mucosa and is detectable via endoscopy using a phenol red indicator. We evaluated whether this test could be used to diagnose H. pylori infection and whether phenol red staining was correlated with (13)C-UBT results.
  
  
  METHODS
  One hundred and twenty-three patients participated. The UBT was performed after ingestion of a capsule containing urea. A change in (13)C-UBT >2 ppt was selected as the cutoff value for diagnosing infection. After spraying evenly with a 0.1% phenol red solution, the pH of the gastric mucosal surface was measured using an antimony electrode through the biopsy channel.
  
  
  RESULTS
  The pH of stained mucosa (6.9+/-0.4) was significantly higher than that of unstained mucosa (1.9+/-0.8; p<0.001), and the H. pylori detection rate confirmed via histology was higher in stained versus unstained mucosa (p<0.01). Extensive mucosal staining resulted in a higher detection rate (p<0.001). The UBT produced results were very similar to those obtained via histological detection in stained mucosa (p<0.001). The extent of staining, expressed as a staining score, was positively correlated with the change in (13)C-UBT (r=0.426, p<0.001). A significant correlation was also observed between the histologically determined H. pylori density and (13)C-UBT results (r=0.674, p<0.001).
  
  
  CONCLUSIONS
  H. pylori infection elevates gastric mucosal surface pH, and endoscopic phenol red staining may be an alternative method for the diagnosis of H. pylori infection.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Young-Seok
authors.initials: YS
authors.lastname: Cho
authors.forename: Hiun-Suk
authors.initials: HS
authors.lastname: Chae
authors.forename: Se Na
authors.initials: SN
authors.lastname: Jang
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Hye Suk
authors.initials: HS
authors.lastname: Son
authors.forename: Hyung-Keun
authors.initials: HK
authors.lastname: Kim
authors.forename: Byung-Wook
authors.initials: BW
authors.lastname: Kim
authors.forename: Sok-Won
authors.initials: SW
authors.lastname: Han
authors.forename: Kyu-Yong
authors.initials: KY
authors.lastname: Choi
authors.forename: Hae Kyung
authors.initials: HK
authors.lastname: Lee
authors.forename: Eun Deok
authors.initials: ED
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D001944:Breath Tests; D004796:Clinical Enzyme Tests; D016099:Endoscopy, Gastrointestinal; D050782:Esophageal pH Monitoring; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010637:Phenolsulfonphthalein; D014510:Urease
chemical_list: D014510:Urease; D010637:Phenolsulfonphthalein
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