Breath tests based on IRMS technology are modern diagnostic tools with a large area of use in gastroenterology. The main topic of this article is the explanation of basic principles of IRMS and its medical applications. Other possibilities of its use in medicine is also mentioned. We present data of Quality Control Assurance including the assessment of „cut-off“ limits for the urea breath test. This test is the most frequent method used in this branch in Czech Republic and in the world.

        Key words: breath test, IRMS, gastroenterology.