A carbon 14 breath test, which tests the digestive tract for H. pylori infection. The price is usually around 100-150 yuan, with some regional and hospital level differences. Before the test, patients need to keep more than 8 hours fasting and stop using antibiotics and bismuth to improve the accuracy of the test results. The carbon 14 breath test test is somewhat radioactive, but not very harmful to health. Helicobacter pylori is a predisposing factor for chronic gastritis, and it is contagious and can be transmitted through the digestive tract. If the carbon 14 test is positive, H. pylori infection can be eradicated with quadruple therapy. Its test results are sensitive and specific, and it is a more commonly used clinical test method.