[New nondispersive infrared spectrometry in 13C-urea breath tests]

13C-urea breath tests have become clinical routine in the diagnosis of Helicobacter pylori infection. For the analysis of the 13CO2/12CO2 enrichment in breath, less expensive alternatives to the expensive mass spectrometry (IRMS) have been developed, based on isotope-selective infrared spectroscopy (NDIRS). In this prospective study we tested under clinical conditions a simplified and thus less expensive NDIR-spectrometer by comparing it with mass spectroscopy.

100 patients (53 men, 47 women, mean age 59+/-14 years) with dyspeptic symptoms were tested for Helicobacter pylori infection using the 13C-urea breath test. The isotope ratio analysis of the breath samples was performed in duplicate, both using IRMS and NDIRS.

The results of the baseline-corrected 13CO2 -exhalation values between IRMS and NDIRS were in excellent agreement. The mean difference between both methods was 0.05+/-1.16 . Evaluating the qualitative urea breath test results in reference to IRMS as the reference, the NDIRS had a sensitivity of 95 % and a specificity of 99 %.

This newly developed isotope-selective nondispersive infrared spectroscopy is going to become a reliable, and low-cost alternative to expensive isotope ratio mass spectrometry in the analysis of 13C-breath tests. All these characteristics make NDIRS particularly suitable for laboratories where the daily number of assays is small or for use in the doctor's office