Determination of the optimal cut-off value for the [13C]-urea breath test based on a Helicobacter pylori-specific polymerase chain reaction assay.
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.
Yoshida
H
H
Department of Gastroenterology, University of Tokyo, Bunkyo, Japan. yoshida-2im@h.u-tokyo.ac.jp
Hirota
K
K
Ogura
K
K
Maeda
S
S
Shiratori
Y
Y
Sasaki
Y
Y
Omata
M
M
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
D002247:Carbon Isotopes; D014508:Urea