Comparison of the 13C-urea breath test and the endoscopic phenol red mucosal pH test in the quantification of Helicobacter pylori infection loading.
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.
Cho
Young-Seok
YS
Department of Internal Medicine, Division of Gastroenterology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Chae
Hiun-Suk
HS
Jang
Se Na
SN
Kim
Jin-Soo
JS
Son
Hye Suk
HS
Kim
Hyung-Keun
HK
Kim
Byung-Wook
BW
Han
Sok-Won
SW
Choi
Kyu-Yong
KY
Lee
Hae Kyung
HK
Chang
Eun Deok
ED
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
D014510:Urease; D010637:Phenolsulfonphthalein
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