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Breath test for Helicobacter pylori: how to prepare, how it is carried out, deciphering, norms
Last reviewed: 05.07.2025
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Many researchers question the fundamental role of Helicobacter Pylori in the pathogenesis of gastritis and peptic ulcer disease, believing that active reproduction of these bacteria begins on the already damaged pyloroduodenal mucosa. However, an indisputable fact is the detection of helicobacteriosis in almost 90% of patients with ulcers and chronic gastritis. Moreover, eradication of this bacterium promotes rapid regression of peptic ulcer disease and provides a long period of remission in patients with ulcerative lesions of the stomach and duodenum. The presence of infection can be diagnosed by various methods - examining smears-prints and biopsies of the mucosa taken endoscopically, determining the presence of antibodies in the blood to Helicobacter Pylori or anthegen in feces. A safe and very effective diagnostic method is the Helicobacter pylori breath test, which uses its ability to produce the hydrolytic catalyst urease, which accelerates the breakdown of urea into ammonia and carbon dioxide. Testing involves a comparative analysis of two samples of exhaled air. The first is taken before taking a solution of urea of normal isotopic composition or with a labeled carbon atom C13, the second - after. This study is quite informative and provides an answer to the question of the presence of Helicobacter Pylor bacteria in the patient and the degree of their activity.
Comparisons of the effectiveness of different methods for studying Helicobacter infection conducted in recent years show the greatest number of positive results when performing a breath test, even in comparison with a microscopic analysis of a biopsy. Experts explain the negative result of histology or polymerase chain reaction with positive results of the urease test by the complexity of culturing the microorganism and the absence of bacteria in the random samples taken. After all, when testing exhaled air, waste products are determined, and not the presence of the microorganisms themselves, which are simply absent in the randomly selected biomaterial.
[ Indications for the procedure a breath test for Helicobacter pylori.
Patients with a confirmed diagnosis of inflammation or ulcerative disease of the digestive tract - esophagus, stomach and/or duodenum, with a history of recurrent Helicobacter pylori infection, and family members of the infected person are subject to testing.
Pain in the epigastrium, discomfort in the abdominal region, dyspeptic disorders - such symptoms are also grounds for referring the patient for a urea breath test.
In this way, both the primary diagnosis of Helicobacter infection and control diagnosis after treatment are carried out.
The attending physician who gives the referral for the examination should have information about where to do a breath urease test for Helicobacter. Unfortunately, district hospitals and rural outpatient clinics, as well as non-specialized medical institutions, as a rule, are not equipped with the necessary equipment to conduct a urease test. Commercial laboratories and specialized gastroenterology clinics in the capitals and large cities have equipment to conduct a breath test for Helicobacter infection. The speed of the analysis and its accuracy depend on the equipment of the laboratory.
Preparation
In order for the test results to be as informative and reliable as possible, the patient must adhere to a number of preparation recommendations. This analysis of exhaled air is carried out in the morning on an empty stomach. The day before, before ten o'clock in the evening, it is allowed to eat an easily digestible dinner.
The day before the scheduled examination, you should not include legumes (soy, peas, beans, etc.) in your diet.
Before the test, you must stop taking antibacterial and secretory activity-reducing medications one to one and a half months before.
Do not take painkillers, anti-inflammatory drugs or antacids for five days prior to the test, and do not take alcoholic beverages or tinctures for three days.
Do not smoke or chew gum three hours before the test.
Before going for testing, make sure to brush your teeth and rinse your mouth thoroughly.
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Technique a breath test for Helicobacter pylori.
Note: During the test, the patient must control their salivation. If discomfort occurs, the breathing tube is removed from the mouth, the saliva is swallowed, and the test is continued. Getting saliva into the breathing tube must be completely excluded, since in this case the test results are considered invalid and the procedure must be repeated in about an hour.
The patient places the plastic tube of the exhaled air analyzer deep enough into the mouth and breathes through it at a normal rhythm several times.
The tube is then removed and the patient is given a urea solution to drink (100 g of urea per 50 ml of water). After which the patient continues to breathe through the tube without straining, at the usual intensity. After the time required for the test, the analyzer is given to the doctor who performs diagnostics, the result is known within a few minutes. Helik diagnostic systems are produced with an indicator tube (the test is performed within a quarter of an hour), a more modern digital model is one where the test result appears on a computer monitor (it takes nine minutes to perform). The procedure is supervised by a doctor. The test with the stable isotope of carbon 13C as a reacting component is considered the most accurate.
Another diagnostic method is to determine the load level of ammonia vapors in the exhalation. The technique is similar, the reagent is cheaper (urea of normal isotopic composition). Its accuracy is estimated as lower. However, it is also quite informative (approximately 85%).
Of all diagnostic methods, the 13C urease breath test for Helicobacter has a number of undeniable advantages. It is carried out without damaging the skin surface and penetrating inside through the natural openings of the body, therefore even minimal injuries during manipulation are excluded. In addition, it is characterized by high specificity and sensitivity (manufacturers estimate these indicators at above 83%), as well as an accuracy of 95-100%.
If the analysis of carbon isotope concentration C13 in this laboratory is done on an infrared (laser) mass spectrometer, then the samples of the patient's exhaled air are transported in a hermetically sealed container to a laboratory equipped with this equipment (sometimes even abroad). The analysis is done within 24 hours, but the exhaled samples are stored for up to 10 days.
Clinicians put the analysis of exhaled air in the first place among the methods of primary diagnostics of Helicobacter infection and monitoring of the effectiveness of treatment. More accurate is only cytological examination of a biopsy taken during endoscopy. But this rather traumatic method is not recommended for all patients, while the urea breath test can be carried out even on pregnant women and children. The isotope of carbon 13C, which labels the urea solution, is natural for the human body. This stable non-radioactive isotope makes up slightly more than 1% of the total amount of carbon in the air exhaled by a person, its remaining part is in the form of 12C. The presence of infection and the catalyst of the urea splitting reaction produced by microorganisms - urease, allows you to quickly start the hydrolysis process. Carbon dioxide containing the labeled atom is absorbed into the blood and leaves the body with the exhalations of the patient. Infrared light is used to examine exhaled breath samples before and after urea use, and the analysis is performed using a mass spectrometer or a rapid Helic test. Based on the ratio of carbon form C13 to C12, a conclusion is made about the presence of infection and its severity. The first version of the study provides high accuracy within 95-100% or more, but not every laboratory has such equipment. And the long process of transportation to equipment equipped with a mass spectrometer can distort the analysis results.
The rapid Helic test has lower sensitivity (about 80-85%), but it is simple and more affordable. It can be performed in any medical institution, since the equipment is portable. The reagent for the test is a solution of ammonia or carbon isotope 13C.
Normal performance
A healthy person should have a negative test result. If the content of the carbon isotope 13C in the air exhaled by the patient does not exceed one ppm (‰), this is the norm for a breath test for Helicobacter. The difference in results between the first stage (before taking urea) and the second (after taking) should be zero or a negative number. The graph shows a constant value of the reagent content relative to the basal level.
A positive result is considered to be more than 1‰ of the 13C isotope in the exhaled air, and there are four degrees of severity of Helicobacter Pylori infection. The norm for a rapid Helicobacter test is the absence of a difference between the indicators before taking the solution and at the second stage after its use. In a Helicobacter-positive patient, the difference exceeds zero, and a pronounced increase in the reagent in the exhaled air is observed on the graph along the ordinate axis.
The value of 1.5-3.4‰ is interpreted as the presence of traces of bacteria, corresponding to the lightest degree of contamination. Bacteria are inactive, you can quickly recover.
A low threshold corresponds to a contamination level of 3.5-5.4‰, while a level of 5.5-6.9‰ is interpreted as low.
The active phase of pathogen reproduction corresponds to values of 7-14.9‰. At this stage, more persistent treatment is predicted, and corresponds to a severe degree of infection.
An extremely severe degree corresponds to a seeding level of 15‰ and higher. The treatment will be persistent and long-term, however, provided that the patient conscientiously follows all medical recommendations, the elimination of Helicobacter Pylori colonies is possible even in this case.
The result obtained after the study on the infrared (laser) mass spectrometer is also defined as a comparative content of carbon isotopes C13 bas in the first sample of the patient's exhalation with C13 cont - a sample after taking the solution. The difference between these parameters is analyzed. A result of no more than 0.3‰ (borderline value) is considered negative; if it is exceeded, the test is considered positive. The mass of dissemination is directly proportional to the value of the indicator.
The device for analysis
In the post-Soviet space, express tests of the patient's exhaled air are more common. They are done on site and do not require transportation or storage of samples. The device for rapid analysis can be equipped with indicator tubes - with a normal reference level of ammonia in the exhaled air and with the patient's exhalation. The presence of bacterial invasion is indicated by a change in the color of the indicator composition in the tube with the analyzed exhalation. The increase in the ammonia level in relation to the standard is determined by millimeter divisions. The result is recorded on the analysis form manually. The duration of the examination is a quarter of an hour.
A more modern and accurate device for conducting a breath test is equipped with a digital sensor. The result is evaluated by a computer program, and it appears on the monitor in the form of a histogram, which can be printed. These devices have a special mouthpiece that protects the breathing tube from saliva. The test takes nine minutes. Provides the greatest accuracy.
The advantage of this equipment over other diagnostic methods, in addition to the already noted safety and absence of contraindications, is portability and compactness, which allows for examination to be carried out literally at the patient's bedside under the supervision of nursing staff. There is no need to transport the biomaterial to laboratories to determine the results. The analysis data does not depend on age, physical condition and the nature of the gastrointestinal tract disease.
Patients who have undergone examination and received any positive results of the breath test for Helicobacter should, without delay, consult a doctor and undergo a course of treatment, which will avoid many unpleasant consequences.