New FTIR methodology for the evaluation of 13C/12C isotope ratio in Helicobacter pylori infection diagnosis

SummaryObjectivesThe objective of this work was to assess the reliability of a newly developed FTIR (Fourier Transform Infrared spectroscopy) technique for 13C-urea breath test in the non-invasive diagnosis of Helicobacter pylori infection, in comparison to those currently used, isotope ratio mass spectrometry (IRMS) and non-dispersive isotope-selective infrared spectrometry (NDIRS). This new methodology is based on the use of a very less expensive and sophisticated FTIR than IRMS and NDIRS.Materials and MethodsSixty patients (male and female, aged between 15–70 years) with dyspeptic symptoms, like the epigastric pain, were tested for H. pylori infection using 13C-urea breath test. Triplicate breath samples were collected before and 30 min after drinking the test solution (75 mg 13C-urea dissolved in 200 ml 0.1 M citric acid). Analysis of δ13C were conducted in parallel by means of IRMS, NDIRS and FTIR in order to compare the results.ResultsDelta-over-baseline values were over 5‰ in 18 patients, ranging from 8.81 to 60.88‰ for IRMS measurements, from 7.2 to 61.2‰ for NDIRS and from 7.7 to 61.2‰ for FTIR measurements. The remaining 42 subjects had values well below the 5‰ cut-off. The results of the baseline-corrected 13CO2 exhalation values between FTIR and IRMS/NDIRS were in good agreement.ConclusionsThe newly developed FTIR methodology has been demonstrated to be a reliable and accurate analytical tool, low cost and easy-to-operate, which permits a highly specific measurement of 13C enrichment in breath samples. As IRMS and NDIRS it allows to adequately discriminate between infected and non-infected subjects.