The first thing you need to do is to get a good understanding of the tests for reflux esophagitis, so that you can achieve an accurate diagnosis of the disease and avoid the risks of the disease. The actual test is a acid perfusion test in which the patient is seated and a gastric tube is placed through the nasal cavity. When the end of the tube reaches 30-35 cm, first drip saline, about 10 ml per minute, for 15 minutes. If the patient has no special discomfort, switch to 0.1N hydrochloric acid and drip at the same rate for 30 minutes. During the drip process, a positive reaction is defined as a painful or burning sensation behind the sternum, which occurs mostly within the first 15 minutes of the drip. If the positive reaction occurs twice, and can be relieved by the saline drip, it can be judged that there is acid GER, and the sensitivity and specificity of the test is about 80%. Beijing Friendship Hospital General Surgery Department Ding Guoqian II Intraluminal pH measurement A pH electrode placed in the lumen is gradually pulled into the esophagus and placed at about 5 cm above the LES. Under normal conditions, the pH in the stomach is very low. At this time, the patient is asked to take a supine position and make movements to increase the pressure in the abdominal pain, such as closing the mouth, covering the nose, exhaling deeply or flexing the legs, and blowing the nose 3 to 4 times. If the pH in the esophagus drops to below 4 times, it indicates the presence of GER. Also, inject 300ml of 0.1N hydrochloric acid into the gastric cavity. Before injecting hydrochloric acid and 15 minutes after injecting, ask the patient to lie on his back and make abdominal pressure increasing movements respectively. In the presence of GER, the pH in the lumen of the esophagus decreased significantly after the injection of hydrochloric acid. In recent years, 24-hour esophageal pH monitoring has become the standard for determining the presence or absence of acidic GER, including the percentage of pH <4 in the esophagus, the percentage of pH <4 in the prone and standing positions, the number of times pH <4, the number of times pH <4 lasts for more than 5 minutes and the longest duration. Our normal 24-hour esophageal pH monitoring has a pH <4 of less than 6% of the time, a number of times lasting more than 5 minutes 3 times, and a maximum duration of reflux of 18 minutes. These parameters can help determine the presence or absence of acid reflux and help elucidate the relationship between chest pain and pulmonary disease and acid reflux. III Esophageal intraluminal pressure measurement The intraluminal pressure is usually measured using a continuous perfusion catheter system filled with water to estimate the function of the LES and esophagus. For pressure measurement, the pressure catheter is first inserted into the stomach, and later, the catheter is withdrawn at a rate of 0.5 to 1.0 cm/min and the intraesophageal pressure is measured. In normal people, the LES pressure at rest is about 2~4kPa15~30mmHg, or the ratio of LES pressure to pressure in the gastric lumen is >1. When the LES pressure at rest is <0.8kPa6mmHg, or the ratio between the two is <1, it indicates that the LES is not functioning properly, or that GER exists. The above mentioned tests for reflux esophagitis are more common in professional hospitals, and we must pay attention to them, because the active grasp of the tests for reflux esophagitis will enable early treatment of the disease to avoid the occurrence of unnecessary risks caused by the disease.