Analysis of the isotopic composition of exhaled air by the diode laser spectroscopy method in the 2-$\mu$m region for diagnosis of Helicobacter pylori-associated diseases

Spectral analysis of $^{13}$СО$_{2}$/$^{12}$СО$_{2}$ isotope ratio in exhaled air based on tunable diode laser spectroscopy was applied for diagnostics of digestive organ diseases associated with Helicobacter pylori infection. Special spectrophotometer based on tunable diode laser was developed for the analysis of breath isotope content. Spectral range near 2.05 microns where the rotational-vibration $R$-branch of the 20013–00001 band of $^{12}$СО$_{2}$ interferes with the $P$-branch of the 20012–00001 band of $^{13}$СО$_{2}$/$^{12}$СО$_{2}$ was used. The $^{13}$C-Urea Breath Test ($^{13}$C-UDT) was used for the H. pylori infection diagnostic in gastrointestinal tract of 309 tested persons. The results of the isotope breath test were compared with the data of morphological analysis of gastric and duodenal mucosa obtained by fibrogastroduodenoscopia. For the first time the total value of the histology analysis results for biopsy material taken in the stomach body, in the distal part of stomach and in the duodenum was proposed to be used for the comparative analysis with $^{13}$C-UBT data. A relationship of $^{13}$C-UBT data with age, nosology, activity and severity of inflammation process, atrophy degree, and type of eradication therapy was analyzed. Distribution of $^{13}$C-UBT data obtained before and after therapy was demonstrated to reflect epidemiology of gastroduodenal diseases, H. pylori infection incidence, specifics of gastrointestinal tract colonization by H. pylori, parameters of inflammation process, as well as therapy effectiveness and peculiarity of the infection restoration at failed eradication therapy.