Before the H. pylori test precautions are as follows: 1, before the examination to maintain a fasting state, to facilitate the doctor to choose the relevant tests; because gastroenterology patients may have to do breath tests to measure H. pylori, may also arrange ultrasound, gastroscopy and other tests; 2, if you choose to do breath tests, it is recommended that patients do not take pills after excessive activity, loud noise, phone calls, etc.; because H. pylori test breath The breath test collects carbon dioxide gas, if too much walking or too much talking may lead to exhaled carbon dioxide set in the air, the collection volume will be reduced, thus affecting the test results; 3, when doing the breath test to select different groups of people, such as children, pregnant women, infants and children or psychiatric patients, may not choose the breath test, but choose stool antigen and serological testing, because the above patients are not cooperative 4, the patient must inform the clinician of the previous medication and the purpose of the visit, because some patients are using antibiotics or acid-suppressing drugs, in this case the breath test results will be affected; the effect of H. pylori eradication requires 4 weeks of drug withdrawal before testing, rather than 2 weeks of drug withdrawal; 5, there are some special circumstances, such as bleeding when the breath test can not be done, may be in The rapid urease test may be done incidentally when doing gastroscopy.