People with duodenal ulcers can use invasive H. pylori testing methods, non-invasive H. pylori testing methods, and based on the results of the tests to determine whether the disease is caused by H. pylori. 1. Invasive H. pylori testing methods (1) Rapid urease test: the accuracy of this test is relatively high. (2) Direct smear: Although this method is relatively simple, it is likely to miss the diagnosis when the amount of bacteria is relatively low. (3) Histologic examination: directly take the gastric body tissue for biopsy, the accuracy is relatively high, but it takes a longer time. 2. Non-invasive H. pylori detection methods (1) Urea breath test: including carbon 13 breath test, carbon 14 breath test, the accuracy is also relatively high, the operation is relatively simple. It is more commonly used in clinical practice. (2) Fecal Helicobacter pylori antigen test: taking feces for corresponding examination is relatively fast, and simple and convenient. To determine whether duodenal ulcer is caused by H. pylori, it is recommended to choose the appropriate test program according to the patient’s specific symptoms and physical condition after the doctor’s interview.