Gastric urea determination

Urea is a test for the presence or absence of Helicobacter pylori (Hp) in the stomach. Because Helicobacter pylori urease uses urea to make ammonia to increase the pH in its surrounding stomach. Urease in gastric juice is a bacterial metabolite, not inherent to the gastric mucosa itself. Helicobacter pylori is the only bacteria in the human stomach that produces large amounts of urea. It has been found that Hp lipopolysaccharide, urease, vacuolating toxin and adhesin are important colonization pathogenic factors, and extracts of Hp can cause DNA damage in gastric mucosal cells. In recent years, studies have shown that various pH values ​​in the stomach do not affect Hp infection, and can still survive when pH<3, indicating that Hp can colonize the stomach in a high acid environment due to urease activity. Basic Information Specialist classification: Digestive examination classification: body fluid examination Applicable gender: whether men and women apply fasting: fasting Reminder: The reagent cup, sample cup and reaction cup should be free of ammonia, clean and free from acid and alkali pollution. Normal value >1 mmol/L. Clinical significance In the general population of China, the infection rate of Hp is between 50% and 80%, which is a highly infected country and can be transmitted orally. In patients with gastric ulcer, the detection rate of Hp is 72%-100%, duodenal ulcer is 73%-100%, and active gastritis is 71%-94%. Epidemiological data support it closely related to the occurrence of gastric cancer. . Hp is: 1. The pathogen of chronic active gastritis. 2. An important pathogenic factor for peptic ulcer. 3. Important pathogenic factors of gastric MALT lymphoma. 4. It may be a synergistic carcinogen of gastric cancer. 5. It is related to functional dyspepsia. Low results may be diseases: Helicobacter pylori infection, Helicobacter pylori infection in children, chronic gastritis, peptic ulcer, functional dyspepsia, gastric cancer precautions 1. The most common problem with this method is the failure of the reagent or the contamination of the reaction system. The most unstable of the reagents are NADH and glutamate dehydrogenase. In the analysis process, attention should be paid to the following aspects: if the specimen is used, the fluorochemical compound or the NH4+ anticoagulant cannot be used. The former can inhibit the urease activity, and the latter can participate in the reaction. 2. The absorbance of the reagent blank should be greater than 1.2A, otherwise the NADH is oxidized. For the same reagents and instruments, the F value should be relatively constant under the condition that the analysis conditions are constant, otherwise the reagent will be invalid. 3. Do not vibrate the reconstituted reagent to avoid deactivation of the enzyme. The reagent must be reconstituted with no ammonia. The reagent cup, sample cup and reaction cup should be free of ammonia, clean and free from acid and alkali pollution. The calibration should be performed each time and the quality control specimen should be followed. Inspection process Gastric juice urea determination method: reagent sample ratio is 70:1, 37 ° C, 340 nm, lag time 30 s, reading time 30 s. The specific analysis conditions can be determined according to the specifications of the kit and the instrument, preferably every time. Not suitable for the crowd Patients with gastric perforation are prohibited from taking gastric juice. Adverse reactions and risks Generally no complications and harm.