Analyzes for Helicobacter pylori

Given the massive population affliction of Helicobacter pylori, its role in the pathogenesis of stomach diseases and the subsequent transition to a cancerous tumor, it is very important to check people at risk for Helicobacter pylori. The same applies to patients with an already diagnosed disease. At them definition Helicobacter gives the chance to learn the reason of illness, to spend specific treatment and to check its productivity.

How to detect an infectious agent that:

• does not grow on normal nutrient media;
• chose "a" gastric juice with sufficient acidity;
• perfectly moves in gel-like mucus due to its flagellum and spiral shape;
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• in case of a dangerous situation is covered with a protective film and takes a spherical shape.

It turned out that this problem is solvable. A feature of most types of analysis for Helicobacter is the identification of not the causative agent itself, but typical changes in the body that it causes.

What types of research are carried out for Helicobacter pylori for diagnosis?

Today, there are several ways to identify Helicobacter pylori in the human body. The optimal method will be advised by the attending physician. The choice depends on the laboratory's capabilities, the patient's condition, age, and the purpose of the study.

Usually prescribed:

• blood test to determine the presence of antibodies, immunoglobulins to Helicobacter pylori, the isolation of specific DNA of microorganisms, the study accurately shows the reaction of antibody formation to a foreign agent and the presence of its gene structures;
• the presence of genetic material can be detected by the analysis of feces on the antigen of the bacterium;
• breath test allows to reveal the urease activity of the pathogen in the stomach, this enzyme( urease) is one of the isolated helicobacteria;
• the most accurate is the cytological examination of the material from the gastric mucosa extracted from fibroadastroduodenoscopy, because it is the only one that is confirmed by the species of the bacterium itself under the microscope.

Consider the advantages and disadvantages of each method of investigation.

The most accurate analysis is obtained by assigning 2 or more different types of diagnostics using different methods

Confirming the presence of Helicobacteria by blood analysis

It is impossible to detect such a bacterium as Helicobacter pylori in blood because it does not enter there. The habitat is limited to the stomach, intestines, drift into the mouth, into the saliva. A specific immune response is formed in response to the introduction of a pathogenic microbe. In the blood appear antibodies and immunoglobulins.

Antibodies are detected by enzyme immunoassay( ELISA).An even more reliable result is the determination of the number of immunoglobulins participating in the formation of immunity.

Venous blood is used for the study. A special substance precipitates the cellular elements and produces a plasma. A small amount is carried to the cells of the tablet, in which the standard antigens are preliminarily introduced.

If there are antibodies in the blood of the person, then the

reaction does not occur at the bottom of the cells. The outcome is confirmed by the application of a paint and a different intensity of staining of the wells. Quantitatively, the result can be taken into account with the help of a spectrophotometric method. The conclusion is given in the digital meaning. Rates of antibodies to Helicobacter pylori in titers are expressed in units of measurement and are determined for each type of immunoglobulins.

The disadvantage of the method lies in the possibilities and laws of the immune system. It should be remembered that:

• antibodies do not appear immediately, they need some time for education( for immunoglobulins of type M - almost a month);
• reaction also means a meeting earlier with a pathogenic microorganism, a borne disease, after which antibodies remain for a long time( in elderly people for life);
• impaired immunity in a patient reflects the reliability of the results of the analysis.

The method gives false-positive and false-negative answers. The only possibility of increasing the diagnostic value of the heliobacter pylori assay is to study each type of immunoglobulin separately and together.

Decoding of the results of the blood test

The peculiarity of the composition of immunoglobulins are:

• IgG is the most common type, it accounts for up to 75% of the total immunoglobulin composition, is produced 3-4 weeks after the "meeting" with the antigen, persists from a month to one and a half years after effective treatment, in some people for life;
• IgA and IgM are the largest protein complexes, but they account for only 10% of all types, are produced rapidly, IgA to Helicobacter pylori can also be detected in the patient's saliva, stomach contents;
• type A shows how high the activity of the inflammatory reaction is.

Method of polymerase chain reaction

The method requires expensive equipment, therefore it is not used in all medical institutions. The essence is not just the detection of antibodies and immunoglobulins, but the DNA of the bacterium itself( the substance that determines the genetic structure).The method is so precise that it can detect a single bacterium.

The analysis is based on multiple doubling of the desired DNA fragment( up to 30-40 copies) according to the given parameters. The copy chain creates enough material for the study. It is more often used at diagnostic difficulties, disagreements in treatment of results.

Conclusion:

• Helicobacter pylori diagnostics for blood analysis should be carried out taking into account the proposed task( to identify the presence of products of exposure to the bacteria, to establish the activity of the inflammatory process, bacteriocarrier, to confirm the cure after the course of therapy);
• type of immunoglobulins indicates an early protective reaction, the consequences of the transferred inflammation;
• should take into account the possibility of false and questionable results;
• to obtain more accurate data requires a comprehensive evaluation of all analyzes.

How is Helicobacter pylori found in feces?

Take for analysis the stool masses - a convenient option for examining patients of children's age, the elderly. The method does not need the presence of the patient himself. It is necessary to take into account the peculiarities of helikobacteria in feces. Bowel environment:

• does not have the necessary acidity;
• is depleted in oxygen;
• is exposed to strong enzyme systems of bile and pancreatic juice.

Quantitatively, the number of bacteria in the intestines is significantly reduced

To identify signs that indicate a Helicobacter bacterium, the polymerase chain reaction method is most suitable. The essence is already described above. Creation of a chain from copies allows to increase the number of detectable DNA segments and to register the involvement of the causative agent in the cause of the patient's disease with an accuracy of up to 95%.

The material for the study can be other than blood and feces:

• saliva;
• urine;
• , expectorated phlegm;
• in pregnant amniotic fluid.

After the course of a special antibacterial treatment, the method will give positive results for a long time in connection with the departure of the destroyed particles of microorganisms.

Urease Respiratory Test

Helicobacter pylori analysis by the urease test is associated with the synthesis of the urease enzyme by the bacterium. It gives the microorganism the ability to exist in gastric juice, cleaves urea to the level of ammonia and carbon dioxide, which is exhaled through the lungs. The procedure has 3 modifications:

• with urea labeled with isotopes of radioactive carbon;
• 13C - urease test;
• Helicopter test.

Modern test systems are equipped with a special protection of the respiratory tube from saliva

Option with isotopes of urea - in the beginning of the study the patient simply breathes into the tube, he takes two air samples. After 15 minutes after ingestion of the labeled urea solution, 4 more samples are taken. When breathing, it is important to swallow the accumulated saliva in a timely manner, if it gets into the samples, it spoils the results and the test has to be repeated.

Ureasal test 13C - the most common in gastroenterological diagnostics. In this embodiment, non-radioactive urea labeled with the 13C isotope is used. The patient has to take only 2 samples of exhaled air in special packages: first on an empty stomach in the morning, the second - 30 minutes after taking the diagnostic solution.

Advantages of the method are:

• precise diagnostics;
• safety in the absence of the use of radioactive materials;
• study duration is within 40 minutes, which is convenient for the patient.

Respiratory Helicopter Test - Urea is used in the modification. It differs by a large intake of the extracted gas after the intake of the urea mixture. The content of the initial air sample is compared with that of carbamide.

The test is considered safe, offered for use in diagnosis to children and pregnant women. But experts do not confirm its sufficient accuracy, therefore, they are rarely used. In conclusion, after carrying out the urease test, the activity will be indicated:

• if found - positive result;
• if not - negative.

Quantitatively, the parameters are determined by a special apparatus( mass spectrometer).It is accepted to assess the analysis for Helicobacter depending on the level of the isotope or its substitute in the exhaled air mixture:

• with a light degree of seeding is 1-3.4%;
• average - 3,5-6,4;
• heavy - 6,5-9,4;
• extremely difficult - any indicators over 9.5%.

It is important to remember that a urease respiratory test is capable of giving a false negative result if the patient had taken medications that lowered the secretory activity of the stomach glands the day before. These drugs block the action of urease bacteria, then the urea ceases to split.

How is the urease express tested?

Helicobacter can be determined by urease activity not only in exhaled air, but also directly in a piece of tissue from the gastric mucosa obtained by fibrogastroscopy. It is sown on a special medium, which, in the case of the presence of urease and ammonia, begins to alkalize. The use of a yellow indicator is accompanied by a change to a crimson coloration.

The evaluation is based on the number of pluses( +), depending on the time required for the color change:

• + - it took at least 24 hours( infection is insignificant);
• ++ - the process took up to three hours( prevalence is moderate);
• +++ - the color changed in an hour( infection is significant).

Biopsy method with cytological assay

The most accurate method of detection is the examination of a cytological material in the form of swabs of mucus obtained from fibroadastroduodenoscopy. Virtually no possibility of false results. The difficulties depend only on the training and experience of the staff.

Helicobacterium under the microscope has a very distinctive appearance with flagella

To quantify, use the denotation of contamination by pluses or the number of microorganisms in the field of view:

• ( +) or weak - marked when detecting up to 20 bacteria in the field of view of the microscope;
• ( ++) or moderate - 20-40 microorganisms;
• ( +++) high - over 40 bacteria.

Do I need to prepare before I pass the analysis?

Where it is possible to pass the analysis on helikobakter the doctor will advise at a direction of the patient. Existing methods often require the participation of a special technical base and training specialists who are not in the polyclinic network. Therefore, you have to use the services of private clinics. It is important to follow the rules how to take the analysis for Helicobacter pylori. There are features with different techniques.

Methods for the detection of antibodies, immunoglobulins require:

• exceptions from the diet 24 hours before the delivery of blood fatty foods, alcohol;
• discontinuation of medicines( antibiotics, non-steroidal anti-inflammatory drugs, hormones) for 14 days;
• limitations of physical work;
• blood sampling on an empty stomach.

At delivery of a feces it is necessary to consider:

• presence of other impurity at diseases of an intestine( slime, pus, a blood);
• the material containing urine is considered unfit;
• should not be treated with antibiotics and Metronidazole until results are obtained;
• prohibition of laxatives in tablets, solution or rectal suppository;
• for three days to exclude from food fiber, salty foods.

If a respiratory urease analysis is assigned by any method, it is necessary: ​​

• in the evening is easy to dine and not eat until the analysis is given;
• for an hour it is forbidden to drink water;
• in the previous 2 days to follow a diet with the exception of black bread, legumes, cabbage, apples( cause increased intestinal gas formation);
• you can not take any alcohol, because even light vapors in the air distort the test results;
• requires smoking cessation to reduce salivation;
• is not recommended to use mouthwashes and mouth fresheners, it is enough to brush your teeth with usual paste;
• for 2 weeks, stop taking drugs that reduce the acidity of gastric juice;
• antibacterial agents and non-steroidal drugs should be discontinued within a week.

To reduce the formation of saliva, you will have to give up the chewing gum

for a while. Who needs to undergo the examination?

The analysis for the detection of Helicobacter pylori in the body is prescribed according to the following indications:

• if a person often feels discomfort in the intestine in the form of incomprehensible pains, increased gas production, grumbling, propensity to diarrhea or constipation, intolerance of some food;
• on a background of complete health, but in the presence of a sick person in the family to detect bacterial transport, even a minimal number of bacteria in conditions of reduced immunity can cause very rapid severe damage to the stomach;
• should not be ignored such a sign as a rapid intoxication from minor doses of alcohol with a pronounced hangover, Helicobacteria disrupt the processes of food processing, the action of enzymes for the absorption of alcohol;
• with incomprehensible pain in the epigastric region, a feeling of heaviness, heartburn;
• deterioration of health after reception of fat and fried food, sharp dishes;
• the patient has attacks of nausea and vomiting.

The quantitative confirmation of the colonization of the stomach with Helicobacteria is necessary: ​​

• for the choice of the method of treatment of gastritis, peptic ulcer;
• detection of infection in the postoperative period of patients with a distant stomach tumor, lymphoma;
• controls the effectiveness of targeted use of medicines.

More than 140 years have passed since the discovery of helikobacteria. Modern scientists are working on proposals for reliable express tests. Life requires the introduction of a quick survey method at the polyclinic level.