13C-Urea breath test, using a new compact nondispersive isotope-selective infrared spectrophotometer: comparison with mass spectrometry.

Background: The (13)C-urea breath test ((13)C-UBT) is the most commonly used noninvasive method of detecting Helicobacter pylori infection. The isotope ratio mass spectrometer (IRMS) is the most commonly used device for this test, but the UBiT-IR300 infrared spectrophotometer, which, by comparison, is a more compact, less expensive, and easier to use analytical device, has now become widely used in the clinical setting in Japan. The objective of this study was to examine the diagnostic performance of the (13)C-UBT, using the UBiT-IR300.

Methods: A multicenter open-label study was performed, in which the (13)C-UBT was conducted using 100 mg of (13)C-urea. Analysis of (13)CO(2) in the expired breath was performed by infrared spectroscopy and mass spectrometry, and assessment of H. pylori infection was performed by culture, histological examination, and rapid urease test.

Results: In 255 cases of H. pylori infection diagnosed by biopsy methods, the (13)C-UBTs, performed with two different (13)C-ruea formulations, and using infrared spectroscopy for evaluation, showed a sensitivity of 97.7%, specificity of 98.0%, and accuracy of 97.8% (total number of evaluable cases, n = 505). The rate of agreement in the assessment of H. pylori infection between infrared spectroscopy and mass spectrometry was 100% ( n = 505). The regression equation for infrared spectroscopy to mass spectrometry was y = 0.9822x - 0.0809 ( n = 2542), with a correlation coefficient of r = 0.99989 ( P = 0.0001).

Conclusions: Diagnosis of H. pylori infection can be performed using infrared spectroscopy as well as mass spectrometry.