Development of a Reference Installation for Metrological Support of the Delta Value Measurements of the Ratio of Carbon and Oxygen Isotopes in Exhaled Air

Abstract

Breath tests in domestic and foreign medicine are recognized as an effective and safe way to identify pathogens in the gastrointestinal tract, in particular the Helicobacter Pylori bacteria. At the end of the 20th century, a urease breath test was introduced into clinical practice to diagnose diseases of the gastrointestinal tract; it was based on the use of urea labeled with a stable isotope 13C ( 13C-urease breath test). The essence was to measure the delta value of the ratio of carbon and oxygen isotopes in exhaled air.Over decades of clinical practice of using this test, a wealth of experience related to the diagnosis of diseases caused, including by the Helicobacter Pylori bacteria has been accumulated. A significant amount of knowledge has also been accumulated in terms of metrological support of the carbon and oxygen isotope delta in exhaled air.The article describes the procedure and results of developing a development of a measurement standard of carbon and oxygen isotope delta in exhaled air, implemented within the R&D a/c No. «Sistema-2020-М» at the D. I. Mendeleyev Institute for Metrology (VNIIM). The authors presented the theoretical study, test methodology, their sequence and results. The article also contains a report on the international comparisons CCQM-P204 “Isotope ratios of CO2 (δ13VPDB and δ18VPDB) in pure CO2” with the application of the measurement standard developed by VNIIM. The metrological characteristics of the measurement standard obtained during the comparisons correspond to the most accurate measurements of the ratio of carbon and oxygen isotopes, which guarantees the recognition of the measurement results at the international level. Considering the high demand for breath tests in medical practice and obvious prospects of this type of diagnostics, further research will be aimed at creating a State Primary Standard for the delta value unit of the ratio of isotopes of carbon, oxygen, hydrogen based on the created measurement standard and the development of certified reference materials of the ratio of isotopes of carbon, oxygen, hydrogen in liquid, solid, and gaseous media, including for the purpose of replacing foreign-made materials.