[Prospective study on the influence of gastroduodenal ulcer hemorrhage on the diagnostic methods in Helicobacter pylori infection].

BACKGROUND: To know the influence of upper gastrointestinal bleeding in diagnostic methods of H. pylori infection.
METHODS: We prospectively studied patients with peptic ulcers: 55 with upper gastrointestinal bleeding and 62 without upper gastrointestinal bleeding. We analysed the results of culture, urease test, Gram, histology and serological test IgG and IgA in both groups. H. pylori infection was determined by a positive culture or positive urease test and histology.
RESULTS: Patients with upper gastrointestinal bleeding were older, but there were not statistical differences in sex, H. pylori prevalence infection or duodenal or gastric ulcers between patients with and without upper gastrointestinal bleeding. 78% having H. pylori infection. The urease test had a false negative rate in patients with upper gastrointestinal bleeding of 22% but only 3% in patients without upper gastrointestinal bleeding (p < 0.05). The culture, histology and Gram had higher false negative rate in upper gastrointestinal bleeding group than in non upper gastrointestinal bleeding group but without statistical significance. All patients with false negative urease test had antral culture positive.
CONCLUSIONS: Urease test has a high false negative rate when is studied in patients with peptic ulcers and upper gastrointestinal bleeding. Caution should be made if urease test was used alone for diagnosis in patients with upper gastrointestinal bleeding. Urease test and culture together could be a good diagnostic method.