The core of the UBT lies in the enzymatic activity of urease, an enzyme that catalyzes the hydrolysis of urea into carbon dioxide (CO2) and ammonia (NH3). During the test, the patient consumes a solution containing isotopically labeled urea, typically with carbon-13 (13C) or carbon-14 (14C). If H. pylori is present in the stomach, the urease enzyme it produces will catalyze the breakdown of the labeled urea. The resulting labeled CO2 is absorbed into the bloodstream and exhaled in the breath, where it can be measured.
