In the clinic, patients often ask me, “Doctor, I often have bloating, belching or acid reflux, and the test says I have H. pylori infection, which I heard can cause cancer! But I’ve taken a lot of medicine, but it’s not working, what should I do?” Many patients know about H. pylori, but they don’t know what to think about the germ or how to treat it. Helicobacter pylori (H. pylori, HP) is a flagellated bacterium that resides in the stomach. It is now clear that H. pylori is the cause of chronic gastritis, peptic ulcer, gastric MALT lymphoma, gastric cancer and some idiopathic thrombocytopenic purpura, and eradication of H. pylori can change the course of the disease. This is not to say, however, that all H. pylori-positive individuals will develop cancer. So, what do we need to be concerned about when it comes to H. pylori? Presence or absence of H. pylori infection The presence or absence of H. pylori infection is the key to determine the next step in management. Among the methods commonly used to detect H. pylori infection, the following are the main ones in addition to gastroscopy: Blood HP-Ab test: The epidemiology of HP infection in the population can be determined by drawing venous blood, but it cannot indicate the presence of presenting infection, and is currently mostly used during routine check-ups. If positive, and if accompanied by certain clinical symptoms, further examination is required. In general, a positive serum HP antibody test indicates a previous infection, and those who have never been treated can be considered as having a current infection. In other words, a blood HP-Ab (+) does not necessarily indicate a current H. pylori infection. Breath test: simpler and easier to perform, but the test must be performed after at least two weeks of proton pump inhibitor (razole class) or H2 receptor blocker class (titin class) drug abstinence before the test; those who apply antibacterial drugs, bismuth and certain herbal medicines with antibacterial effects should be tested after at least 4 weeks of drug discontinuation. It should be reminded that this type of test is an isotope test with a very low dose of radiation. Fecal HP test: The fecal HP antigen test is noninvasive and specific, and is a good method for detecting presenting H. pylori infection. However, the test reagents are more expensive and still not widespread in the clinic, so it is mainly used in research. In addition, there are genetic testing methods, such as PCR, oligonucleotide probe hybridization, and gene chip testing, which are also not routinely used in clinical practice. Do I have H. pylori infection? If one of the following 3 items is met, you can be judged to have HP infection. ①Gastric mucosal tissue rapid urease test, tissue section staining or culture, positive for any one of the 3 items. ② Positive for 13C or 14C-UBT. ③ Positive HpSA test (HP fecal antigen test, clinically validated monoclonal antibody method). It should be noted that there are differences in the accuracy of different testing reagents, and the applied reagents and methods need to be validated; the accuracy of the test results can be affected by differences in operators and operating methods; certain drugs can have an effect on the test results; different disease states can also have an effect on the test results, such as active bleeding from peptic ulcer, severe atrophic gastritis, and gastric malignancy may lead to urease dependent test false negatives, etc. Therefore, more reliable results can be obtained at different times, by using multiple methods or by using non-urease dependent test; the results of HP detection by breath test are not reliable in people with residual stomach, and urease method, tissue section method or HpSA method are recommended; HP detection rate in gastric mucosal intestinal raw tissue is low. Therefore, in the above cases, if the HP test is negative, false negatives should be highly suspected and more reliable results can be obtained by testing at different times or using multiple methods. Who should eradicate H. pylori According to the Fourth National Consensus Report on the Management of H. pylori Infection, H. pylori should be eradicated in the following categories: peptic ulcer (with or without activity and history of complications), lymphoma of gastric mucosa-associated lymphoid tissue, chronic gastritis with dyspeptic symptoms, early gastric tumors that have been surgically removed, long-term use of proton pump inhibitors, family history of gastric cancer, planned long-term NSAIDs (including low-dose aspirin), unexplained iron deficiency anemia, idiopathic thrombocytopenic purpura, and other H. pylori-associated diseases. How to choose eradication methods There are two commonly used methods for H. pylori eradication: a triple regimen, which includes a proton pump inhibitor (PPI) and two antibiotics, taken for 14 days; and a quadruple regimen, which adds bismuth to the triple regimen, taken for 10 days. The specific regimen selection should be considered from multiple perspectives, such as the patient’s age, condition, and antibiotic resistance in the location, and should be decided by a specialist. If eradication treatment is performed, patients must be retested for H. pylori 4 weeks after the end of treatment or 4 weeks later, and HP eradication can be judged by meeting one of the following 3 items: ① negative 13C or 14C-breath test. ②Negative HpSA test. (iii) Negative rapid urease test based on both sinus and gastric body sampling. The breath test may be preferred. Drug resistance needs to be taken into account when H. pylori is not eradicated on review, and drug sensitivity testing should be performed before eradication therapy if necessary.