Final answer:
The breath test for Helicobacter pylori infection detects the presence of radiolabeled carbon dioxide in a patient's breath, which is produced when the bacterium breaks down urea.
Step-by-step explanation:
The "breath test" for Helicobacter pylori infection detects the presence of carbon dioxide (CO2). When a patient ingests radioactively labeled urea, if H. pylori bacteria are present in the stomach, they produce an enzyme called urease, which breaks down the urea into carbon dioxide and ammonia. In this test, the resulting carbon dioxide is radiolabeled, and its presence in the patient's breath can be detected, indicating an H. pylori infection.