title: Breath sample collection through the nostril reduces false-positive results of 13C-urea breath test for the diagnosis of helicobacter pylori infection.
abstract: BACKGROUND
  One of the disadvantages of '3C-urea breath test is possible interference by urease activity not related to Helicobacterpylori.
  
  
  OBJECTIVE
  We design the simple and non-invasive modification to avoid the contamination of 13CO(2) produced in the mouth.
  
  
  METHODS
  One hundred and twenty-nine patients who underwent diagnostic upper endoscopy were enrolled. Within 1 week of the endoscopic procedure, each patient received the modified 13C-urea breath test. Breath samples were collected at baseline and at 1, 3, 5, 10, 15, 20 and 30 min after ingestion of 100 mg 13C-urea solution through the mouth and the nostril at each time point.
  
  
  RESULTS
  The breath delta13CO2 value through the nostril at 1 min was already higher in H. pylori-positive patients than in H. pylori-negative patients. Using 2.5% as the cut-off value, the sensitivity and specificity of the modified 13C-urea breath test at 20 min were both 100%, whereas the sensitivity and specificity of the standard 13C-urea breath test were 97.7 and 94%, respectively, using 3% as the cut-off value.
  
  
  CONCLUSIONS
  The modified 13C-urea breath test in which breath samples are collected through the nostril provides an easy way of avoiding false-positive results for the detection of H. pylori infection.
authors.affiliation: Division of Gastroenterology and Hepatology, Toho University School of Medicine, Tokyo, Japan. foo@eb.mbn.or.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Urita
authors.forename: K
authors.initials: K
authors.lastname: Hike
authors.forename: N
authors.initials: N
authors.lastname: Torii
authors.forename: Y
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: E
authors.initials: E
authors.lastname: Kanda
authors.forename: H
authors.initials: H
authors.lastname: Kurakata
authors.forename: M
authors.initials: M
authors.lastname: Sasajima
authors.forename: K
authors.initials: K
authors.lastname: Miki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001944:Breath Tests / Q000379:methods*; D002247:Carbon Isotopes; D016099:Endoscopy, Gastrointestinal; D005189:False Positive Reactions; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori / Q000302:isolation & purification*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D014508:Urea / Q000302:isolation & purification*
chemical_list: D002247:Carbon Isotopes; D014508:Urea