Both Carbon-13 and Carbon-14 breath test can be used to detect H. pylori, and their differences mainly lie in the labeling method, radioactivity, and applicable population. 1. Labeling method: Carbon-13 is a test reagent labeled with carbon-13 isotope, and carbon-14 is a test reagent labeled with carbon-14 isotope. 2. Radioactivity: In the Carbon 13 breath test, elemental carbon is relatively stable and less radioactive. Carbon-14 is not as stable as Carbon-13 and has a small amount of radioactivity, but the radiation distance is relatively short. 3. Applicable population: Carbon-13 breath test is suitable for children, pregnant women and lactating women, but Carbon-14 breath test is not suitable for pregnant women and lactating women. The diagnostic accuracy of the two methods is basically no significant difference, and the price of carbon 14 is relatively low, ordinary adults can also choose carbon 14 for examination, pregnant women, children and other special groups are recommended to choose carbon 13 breath test.