title: Appropriate cut-off value of 13C-urea breath test after eradication of Helicobacter pylori infection in Japan.
abstract: OBJECTIVE
  A cut-off value of 2.5 per thousand for the 13C-urea breath test (UBT) is recommended in Japanese persons, based on the result of a multicenter trial in patients prior to treatment for eradication of Helicobacter pylori. The cut-off value of 2.5 per thousand has also been used in the assessment of eradication after treatment. The 6-8-week evaluation after treatment is recommended in the guidelines of the Japanese Society of Gastroenterology. The present study aimed to prospectively re-assess the cut-off value of the 13C-UBT at 6 weeks after treatment by using the results obtained at 6 months as an indication of true positive or true negative H. pylori infection status.
  
  
  METHODS
  One hundred and ninety patients who were positive for H. pylori underwent eradication treatment, and 177 patients of these patients who were assessed as having true positive or true negative H. pylori status at 6 months after treatment were evaluated in this study. Eradication was assessed by 13C-UBT, culture, and histology at 6 weeks and at 6 months after treatment, and the cut-off value of 13C-UBT at 6 weeks was re-assessed.
  
  
  RESULTS
  A cut-off value of 3.5 per thousand. at 6 weeks after treatment showed 97.2% diagnostic accuracy, while a cut-off value of 2.5 per thousand at 6 weeks showed 96.0% diagnostic accuracy. For a 3.5 per thousand cut-off value, only five patients were positive by 13C-UBT and were negative by culture and histology at 6 weeks, and three patients were true positive and two were false positive by the 13C-UBT at 6 months.
  
  
  CONCLUSIONS
  A cut-off value of 3.5 per thousand for the 13C-UBT is recommended at 6 weeks after eradication treatment in Japanese persons.
authors.affiliation: First Department of Internal Medicine, Iwate Medical University, Morioka, Japan.
authors.forename: Chieko
authors.initials: C
authors.lastname: Kato
authors.forename: Toshiro
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Kunio
authors.initials: K
authors.lastname: Sato
authors.forename: Shinji
authors.initials: S
authors.lastname: Saito
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kudara
authors.forename: Yukito
authors.initials: Y
authors.lastname: Abiko
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Toshimi
authors.initials: T
authors.lastname: Chiba
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Satoh
authors.forename: Takashi
authors.initials: T
authors.lastname: Akihama
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Suzuki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001944:Breath Tests; D002247:Carbon Isotopes / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000378:metabolism; D016480:Helicobacter pylori / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D016896:Treatment Outcome; D014508:Urea / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D014508:Urea