A positive carbon urea breath is generally defined as a positive carbon 13 or carbon 14 breath test, which refers to the presence of gastric Helicobacter pylori infection. The carbon 13 or carbon 14 breath test, which is used clinically to detect gastric H. pylori, is a simple, quick, and painless test that is suitable for most subjects. The normal range for carbon 14 is 0-100, and when the test value is greater than 100, the test is positive for H. pylori infection. Carbon 13 has a normal range of 0-4, with a value greater than 4 indicating a positive test. Fasting is required before both the carbon 13 and carbon 14 tests, and the carbon 13 test is not radioactive. As H. pylori is contagious, it is recommended to share meals and use chopsticks when eating together. If you have any gastrointestinal symptoms, it is recommended that you consult a doctor promptly to avoid delays.