Introduction to Helicobacter pylori Helicobacter pylori mainly resides in the human stomach, Hp is the causative agent of many gastric diseases and is the main culprit of peptic ulcer and chronic active gastritis, and is also recognized by the World Health Organization as the first class carcinogen of gastric cancer. Hp infection is present in more than 90% of duodenal ulcers and more than 70% of gastric ulcers, and eradication of Hp is a prerequisite for curing gastric diseases. H. pylori is highly contagious and can be transmitted through hands, unclean food, and feces. There are many ways to check for H. pylori, including blood draws, gastroscopy and breath tests. Among them, breath test to detect H. pylori is convenient, accurate and painless popular among people. This article introduces what we often hear about the breath test to determine if you are infected with H. pylori, and is it a substitute for a gastroscopy? The scientific name for the “breath” test for H. pylori is the carbon 13 (or carbon 14) urea breath test, hereinafter referred to as the breath test. It is based on the principle of using the carbon isotope “carbon 14 or carbon 13” as a marker to label the carbon atoms in urea, and using the characteristics of H. pylori to decompose urea to determine the presence of this bacterium. If H. pylori is present in the stomach after oral administration of a labeled urea capsule, the urease produced by the capsule will break down the labeled urea into carbon dioxide and ammonia, and the carbon atoms in the urea will move to carbon dioxide, which will be excreted from the lungs through the bloodstream, and the excreted carbon dioxide will be collected (by blowing or exhaling). The presence or absence of H. pylori infection in the stomach can be determined by measuring the level of carbon dioxide produced from the breakdown of H. pylori by a specific instrument. There are two commonly used markers, C14 and C13. The C14 test is inexpensive but radioactive and cannot be used in pregnant women and those recently preparing for pregnancy and in children. C13 is a stable isotope that occurs naturally in nature in specific proportions and is therefore not radioactive and is suitable for all ages and types of subjects, including pregnant women and children. C13 is highly accurate in diagnosing Hp infection and determining the efficacy of Hp eradication in domestic and foreign workers. Advantages of the “breath method” Accuracy Gastroscopic H. pylori testing has a certain probability of missing the test, and the sampling site just does not have H. pylori, resulting in false negatives. The C13 or C14 urea breath test overcomes this deficiency and allows for an overall assessment of the severity of H. pylori infection in the stomach, independent of sampling errors in the focal distribution. The sensitivity and specificity of the urea breath test are high and it has been recognized as the best method available for detecting H. pylori. Convenient and painless The ability to detect H. pylori without a gastroscopy is, I am afraid, the greatest advantage of the breath test. The breath test can replace gastroscopy in terms of accuracy in detecting H. pylori and is also less expensive than gastroscopy. After the eradication of H. pylori, the effect of treatment can be reviewed by breath test, and it should be done after 4 weeks of drug withdrawal. The test is performed by taking a capsule orally for three hours on an empty stomach and then exhaling half an hour later to obtain a sample. The breath test requires an empty stomach and may interfere with the test results if medication has been used recently. The breath test is not a substitute for a gastroscopy. Invasive tests such as gastroscopy are revered by most patients, and the breath test is widely preferred. It is important to emphasize that breath testing can accurately determine the presence of H. pylori in the stomach, but it is not a substitute for gastroscopy. Some inappropriate propaganda, such as “gently blow, you can check the stomach disease” mislead many patients. This kind of propaganda and advertising has changed the concept and expanded the function of the breath test, which can only detect the presence of H. pylori infection, and a negative breath test is not the same as the absence of gastric disease. The breath test is a targeted test, while gastroscopy can determine inflammation, ulcers, polyps or tumors in the stomach in addition to detecting Hp. If you have “gastric disease”, a breath test alone cannot accurately determine what kind of gastric disease, but only know whether there is H. pylori infection, whether the pain is caused by ulcers or tumors need gastroscopy to be clear. “There are many different types of gastric diseases, and there is no direct equation between H. pylori infection and “gastric disease”. Therefore, a breath test is not a substitute for a gastroscopy, and a gastroscopy is needed to diagnose what kind of gastric disease is present. A breath test is a convenient and accurate way to detect the presence of H. pylori infection, but it has a single function. A negative breath test is not the same as the absence of gastric disease, and a gastroscopy is no substitute for a truly comprehensive understanding of the stomach.