title: Mucosal polymerase chain reaction for diagnosing Helicobacter pylori infection in patients with bleeding peptic ulcers.
abstract: OBJECTIVE
  Helicobacter pylori (H pylori) has been linked to chronic gastritis, peptic ulcers, gastric cancer and MALT-lymphoma. Conventional invasive tests are less sensitive than non-invasive tests in diagnosing H pylori infection in patients with bleeding peptic ulcers. Polymerase chain reaction is a sensitive and accurate method for diagnosing H pylori infection. The aim of this study was to evaluate the diagnostic role of mucosal polymerase chain reaction for H pylori infection in patients with bleeding peptic ulcers.
  
  
  METHODS
  In patients with bleeding, non-bleeding peptic ulcers and chronic gastritis, we checked rapid urease test, histology, bacterial culture and mucosal polymerase chain reaction for detecting H pylori infection. Positive H pylori infection was defined as positive culture or both a positive histology and a positive rapid urease test. For mucosal polymerase chain reaction of H pylori, we checked vacA (s1a, s1b, s1c, s2, m1, m1T, m2), iceA1, iceA2 and cag A.
  
  
  RESULTS
  Between October 2000 and April 2002, 88 patients with bleeding peptic ulcers (males/females: 60/28, gastric ulcers/duodenal ulcers: 55/33), 81 patients with non-bleeding peptic ulcers (males/females: 54/27, gastric ulcers/duodenal ulcers: 45/36) and 37 patients with chronic gastritis (males/females: 24/13) were enrolled in this study. In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, 45 patients (51%), 71 patients (88%) and 20 patients (54%) respectively were found to have positive H pylori infection (P<0.001). In patients with bleeding peptic ulcers, non-bleeding peptic ulcers and chronic gastritis, polymerase chain reaction for H pylori infection was positive in 54 patients (61%), 70 patients (86%) and 20 patients (54%) respectively (P<0.001). The sensitivity, positive predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori infection were significantly lower in patients with bleeding peptic ulcers (84%, 79% and 81%) than in patients with non-bleeding peptic ulcers (99%, 99% and 98%) (P<0.001, P<0.01 and P<0.001 respectively). The sensitivity, negative predictive value and diagnostic accuracy of mucosal polymerase reaction for H pylori were significantly lower in patients with bleeding peptic ulcers (84%, 83% and 81%) than in patients with chronic gastritis (100%, 100% and 100%) (P = 0.02, P = 0.02 and P = 0.001).
  
  
  CONCLUSIONS
  Mucosal polymerase chain reaction for detecting H pylori infection is not reliable in patients with bleeding peptic ulcers.
authors.affiliation: Division of Gastroenterology, Department of Medicine, VGH-Taipei, Taiwan, China. 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: Guan-Ying
authors.initials: GY
authors.lastname: Tseng
authors.forename: Anna-Fen-Yau
authors.initials: AF
authors.lastname: Li
authors.forename: Yueh-Hsing
authors.initials: YH
authors.lastname: Ou
mesh_terms: D000368:Aged; D005260:Female; D005753:Gastric Mucosa / Q000378:metabolism*; D005756:Gastritis / Q000382:microbiology; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D010437:Peptic Ulcer / Q000382:microbiology; D010438:Peptic Ulcer Hemorrhage / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000592:standards*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity