title: Helicobacter pylori stool antigen test in patients with bleeding peptic ulcers.
abstract: BACKGROUND
  Helicobacter pylori has been linked to chronic gastritis, peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Invasive tests are less sensitive than noninvasive tests in diagnosing H. pylori infection in patients with bleeding peptic ulcers. The H. pylori stool antigen test has been useful in diagnosing H. pylori in patients with peptic ulcers before and after eradication of H. pylori. The aim of this study was to evaluate the H. pylori stool antigen test in patients with bleeding peptic ulcers.
  
  
  METHODS
  Patients with bleeding and nonbleeding peptic ulcers underwent a rapid urease test, histology, bacterial culture and H. pylori stool antigen test. Positive H. pylori infection was defined as a positive culture or both a positive histology and a positive rapid urease test. Helicobacter pylori stool antigen was assessed with a commercial kit (Diagnostec H. pylori antigen EIA Kit, Hong Kong).
  
  
  RESULTS
  Between October 2000 and April 2002, 93 patients with bleeding peptic ulcers (men/women: 78/15, gastric ulcer/duodenal ulcer: 58/35) and 59 patients with nonbleeding peptic ulcers (men/women: 47/12, gastric ulcer/duodenal ulcer: 30/29) were enrolled in this study. Forty-seven (50.5%) patients with bleeding peptic ulcers and 30 (50.8%) patients with nonbleeding peptic ulcers, were found to be infected with H. pylori (p > .1). Helicobacter pylori stool antigen tests were positive in 54 (58.1%) and 30 (50.8%) patients with bleeding peptic ulcers and nonbleeding peptic ulcers, respectively (p > .1). The sensitivity (82% vs. 93%), specificity (68% vs. 93%), positive predictive value (74% vs. 93%), negative predictive value (77% vs. 93%) and diagnostic accuracy (75% vs. 93%) were all lower in patients with bleeding vs. nonbleeding peptic ulcers. The specificity, positive predictive value, and diagnostic accuracy of the H. pylori stool antigen test in patients with bleeding peptic ulcers were significantly lower than those in patients with nonbleeding peptic ulcers (p = .01, p = .02 and p = .003, respectively).
  
  
  CONCLUSIONS
  The H. pylori stool antigen test is not reliable for diagnosing H. pylori infection in patients with bleeding peptic ulcers.
authors.affiliation: Division of Gastroenterology, Department of Medicine, VGH-TAIPEI, Taipei, Taiwan. hjlin@vghtpe.gov.tw
authors.forename: Hwai-Jeng
authors.initials: HJ
authors.lastname: Lin
authors.forename: Wen-Ching
authors.initials: WC
authors.lastname: Lo
authors.forename: Chin-Lin
authors.initials: CL
authors.lastname: Perng
authors.forename: Anna Fen-Yau
authors.initials: AF
authors.lastname: Li
authors.forename: Guan-Ying
authors.initials: GY
authors.lastname: Tseng
authors.forename: I-Chen
authors.initials: IC
authors.lastname: Sun
authors.forename: Yueh-Hsing
authors.initials: YH
authors.lastname: Ou
mesh_terms: D000368:Aged; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial / Q000032:analysis*; D005243:Feces / Q000382:microbiology*; D005260:Female; D005753:Gastric Mucosa / Q000473:pathology; D016481:Helicobacter Infections / Q000150:complications / Q000175:diagnosis*; D016480:Helicobacter pylori / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010437:Peptic Ulcer / Q000175:diagnosis* / Q000382:microbiology / Q000473:pathology; D010438:Peptic Ulcer Hemorrhage; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D014510:Urease / Q000032:analysis
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D014510:Urease