title: Determination of the optimal cut-off value for the [13C]-urea breath test based on a Helicobacter pylori-specific polymerase chain reaction assay.
abstract: BACKGROUND
  This study was conducted to determine the optimal cut-off value and breath sample collection time for the [13C]-urea breath test based on the assessment of Helicobacter pylori status with a gastric juice-based polymerase chain reaction (PCR) assay.
  
  
  RESULTS
  A total of 104 patients took 100 mg [13C]-urea orally and breath samples were collected at 5, 10, 20, 30 and 60 min. The increment of 13CO2:12CO, ratio from the baseline (delta13C) was measured using a laser spectroanalyser. The PCR assay was positive in 63 and negative in 41 patients. The optimal cut-off value of delta13C was calculated for each sample collection time so that the distance from the geometric mean value among Helicobacter pylori-positive patients and that from the arithmetic mean value among negative patients were simultaneously maximized. The cut-off value of 2.7% at 20 min had the longest distance, being separated by 3.16 SD from the two mean values. Using this cut-off value, the urea breath test showed 100% specificity and 98% sensitivity for the diagnosis of Helicobacter pylori infection.
authors.affiliation: Department of Gastroenterology, University of Tokyo, Bunkyo, Japan. yoshida-2im@h.u-tokyo.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Yoshida
authors.forename: K
authors.initials: K
authors.lastname: Hirota
authors.forename: K
authors.initials: K
authors.lastname: Ogura
authors.forename: S
authors.initials: S
authors.lastname: Maeda
authors.forename: Y
authors.initials: Y
authors.lastname: Shiratori
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
authors.forename: M
authors.initials: M
authors.lastname: Omata
mesh_terms: D001944:Breath Tests; D002247:Carbon Isotopes; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis*; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D013997:Time Factors; D014508:Urea
chemical_list: D002247:Carbon Isotopes; D014508:Urea