Nondispersive infrared spectrometry for (CO2)-C-13/(CO2)-C-12-measurements: A clinically feasible analyzer for stable isotope breath tests in gastroenterology

Background: C-13-urea breath tests have become clinical routine for the dia gnosis of Helicobacter pylori infection and other isotope breath tests have been invented e.g. for gastric emptying or quantitative liver. function te sting. Recently, isotope-selective nondispersive infrared spectrometers (ND IRS) hale been developed for the analysis of the (CO2)-C-13/(CO2-)-C-12 enr ichment in breath. In this study, we prospectively tested the validity of a newly developed NDIRS in comparison to isotope ratio mass spectrometry (IR MS). Methods: 142 patients with dyspeptic symptoms were tested for Helicobacter pylori infection using the C-13-urea breath test. The isotope ratio analysi s of the breath samples was performed in duplicate both using IRMS and NDIR S. Results: The results of the baseline-corrected (CO2)-C-13-exhalation values between IRMS and NDIRS were in excellent agreement. The mean difference be tween both methods was 0.28 +/- 1.93 delta parts per thousand. Evaluating t he qualitative urea breath test results in reference to IRMS as the referen ce the NDIRS had a sensitivity of 97.8% and a specificity of 98.9%. Conclusion: The isotope-selective nondispersive infrared spectroscopy is go ing to become a reliable, but low-cost and easy-to-operate alternative to e xpensive isotope ratio mass spectrometry in the analysis of C-13-breath tes ts.