title: Diagnosis of Helicobacter pylori in bleeding peptic ulcer patients, evaluation of urea-based tests.
abstract: OBJECTIVE
  The prevalence of Helicobacter pylori (Hp) has been reported to be lower in patients with bleeding peptic ulcers than in patients with nonbleeding peptic ulcers. This might be due to inaccuracy of the urease-based diagnostic tests when used in patients with bleeding peptic ulcers. The aims of this study were to compare the validity of the rapid urease test (RUT) and (13)C-urea breath test in patients with bleeding (group 1) and nonbleeding peptic ulcers (group 2) and to examine whether the presence of blood in the stomach influences the validity of urease-based tests.
  
  
  METHODS
  95 consecutive patients with bleeding peptic ulcers (48 with and 47 without blood in the stomach) and 44 with uncomplicated peptic ulcers. Biopsies for RUT and histology were obtained during endoscopy. After endoscopy a (13)C-urea breath test was performed. Positive histology was used as 'gold standard' defining positive Hp-status.
  
  
  RESULTS
  The prevalence of Hp-infection was 44/95 (46%) in group 1 and 29/44 (66%) in group 2 (p = 0.04). The sensitivities and specificities of RUT, (13)C-urea breath test and serology (control) were between 0.72 and 0.96; no difference was found between the groups. In group 1 the sensitivity of the RUT decreased from 0.96 when no blood was present to 0.60 when blood was present (p = 0.006). The sensitivity of (13)C-urea breath test was not affected by blood in the stomach.
  
  
  CONCLUSIONS
  When comparing patients with bleeding and nonbleeding peptic ulcers, we did not find any difference in either sensitivity or specificity of the diagnostic tests for Hp. However, the sensitivity of the RUT was lower when blood was present in the stomach, which was the case in only half of the patients. The sensitivity and specificity of the (13)C-urea breath test was not affected by the presence of blood in the stomach.
authors.affiliation: Department of Medical Gastroenterology S, Odense University Hospital, Odense, Denmark. mette.wildner.christensen@ouh.fyns.amt.dk
authors.forename: Mette
authors.initials: M
authors.lastname: Wildner-Christensen
authors.forename: Annmarie
authors.initials: A
authors.lastname: Touborg Lassen
authors.forename: Jan
authors.initials: J
authors.lastname: Lindebjerg
authors.forename: Ove B
authors.initials: OB
authors.lastname: Schaffalitzky de Muckadell
mesh_terms: D000368:Aged; D001944:Breath Tests; D002247:Carbon Isotopes; D016022:Case-Control Studies; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D010438:Peptic Ulcer Hemorrhage / Q000382:microbiology*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014508:Urea; D014510:Urease / Q000032:analysis*
chemical_list: D002247:Carbon Isotopes; D014508:Urea; D014510:Urease