Breathing test for Helicobacter pylori: indications, preparation, interpretation of results
The content of the article:
- Indications for a breath test
- Preparing for the breath test
- How is the Helicobacter pylori breath test performed?
- Decoding the results
The breath test for Helicobacter pylori (Helicobacter pylori) is a quick and safe test that allows you to identify the bacteria that cause chronic gastritis and stomach ulcers. After entering the body, the bacterium moves along the mucous membrane of the stomach with the help of flagella and is fixed on its walls. The microorganism produces substances that destroy the epithelial cells of the gastric mucosa, and releases toxins that cause immune diseases. Trying to protect itself from a parasitic microorganism, the stomach increases the secretion of hydrochloric acid and substances that destroy its walls. However, the bacterium is able to survive for a long time in an acidic environment due to the enzyme it secretes - urease, which protects the microorganism from the effects of gastric juice.
A breath test for Helicobacter pylori is performed when a possible infection is suspected, and also to monitor therapy
Urease tends to break down urea (urea) in the stomach contents to ammonia and carbon dioxide, which neutralize hydrochloric acid. In this case, the acidity of the medium shifts to the alkaline side, which can be fixed using an indicator. The resulting carbon dioxide is absorbed into the blood, with which it enters the lungs, and then into the exhaled air. The breath test is based on measuring the concentration of urea and its decay products in the exhaled air.
Indications for a breath test
A breath test for Helicobacter pylori is performed in the following cases:
- early diagnosis of H. pylori-associated chronic gastritis;
- dyspeptic complaints (discomfort in the stomach and intestines, pain in the stomach and duodenum, bad breath, heartburn, nausea, vomiting, loss of appetite, feeling of heaviness after eating, increased gas production, rumbling in the abdomen, upset stools);
- determination of the risk of gastric ulcer and 12 duodenal ulcer;
- epidemiological studies (identification of infection of family members or persons in close contact with the patient);
- screening before endoscopy;
- observation of the patient after treatment of Helicobacter pylori infection.
Preparing for the breath test
Diagnostics is carried out in the morning.
In preparation for the study, the patient must adhere to the following rules:
- stop taking antibiotics a month before passing the urease breath test;
- 14 days before the examination, exclude the use of antisecretory and antihistamines, a few days - antacids, bismuth preparations and analgesics;
- do not drink alcohol 3 days before the examination;
- during the day before taking the analysis, it is recommended not to eat fatty, fried foods, pickles, sweets and legumes;
- there must be at least eight hours between the last meal and the breath test;
- on the day of the test, you need to stop smoking, use chewing gum;
- Before the procedure, you should thoroughly brush your teeth.
How is the Helicobacter pylori breath test performed?
The labeled urea breath test is based on the determination of the concentration of urea. The test allows not only to confirm or exclude the infection, but also to determine the quantitative indicators of bacteria in the body: the more bacteria there are, the higher the urease activity.
For the analysis, the patient is asked to hold his breath for a few minutes and exhale the air into a container or plastic tube. This sample is used as a control (baseline). After that, as a load, the subject takes a urea solution, which contains a non-radioactive stable labeled isotope of carbon 13 C. After a while, the patient exhales air into another test tube.
Analysis of the baseline and loading level of the 13 C isotope in exhaled air is carried out using a diagnostic gas mass spectrometer or a less sensitive infrared IR spectrometer.
The disadvantages of this method include the high cost of diagnostic equipment and an isotope for the test.
A less expensive method of analysis - ammonia breathing rapid test (a test system Helic ® digital analyzer). The level of urease activity in the stomach in this case is assessed by the change in the concentration of ammonia in the exhaled air. The method is based on recording the increase in the concentration of ammonia in the oral cavity, which increases in the exhaled air after taking urea. Gas appears in the oral cavity within 6-7 minutes after taking the load. In this case, the indicator tube connected to the device changes its color. During the study, it is necessary to ensure that saliva does not enter the tube.
The HELIK test has high sensitivity and accuracy; it does not require sophisticated equipment and the use of isotopes of a changed composition. The duration of the analysis is approximately 15 minutes, the result can be obtained directly during the study.
Decoding the results
Analyzing the information received, the doctor concludes that the patient is infected.
If there are no bacteria in the body, then the concentration of carbon dioxide with carbon 13 C in the exhaled air will be equal to its concentration before taking an aqueous solution of urea. If the stress test contains a lot of carbon dioxide labeled with 13 C, this means that the patient is infected with Helicobacter Pylori.
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Anna Kozlova Medical journalist About the author
Education: Rostov State Medical University, specialty "General Medicine".
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