Blood test for Helicobacter pylori

Not every case of stomach and duodenal pathology is caused by Helicobacter pylori infection. Its participation in statistical research is attributed to 70%( among cases of stomach ulcers up to 38%, ulcers of the duodenum - 56%).The most reliable fact is the detection of this microorganism directly in the mucous membrane of the stomach, it does not live in the blood.

However, a blood test for Helicobacter pylori is able to show the results of the presence of the pathogen. This is important for diagnosing and selecting a patient's treatment. Comparison of the obtained numerical values ​​of deviations with the norm is taken into account when deciphering the blood test for Helicobacter pylori and allows to predict the course of the disease.

A little about the characteristics of helikobacteria

The literal Greek-Greek name Helicobacter pylori( "spiral-shaped gatekeeper") is associated with the characteristic shape of the bacterium and maximum living in the transition zone from the stomach to the duodenum( gatekeeper).

With the help of flagella, mobility and the ability to move in the gel-like mucus environment on the inner surface of the stomach are provided. This is the only microorganism able to live in an acidic environment.

From opening in 1875 to the awarding of the Nobel Prize in 2005, 130 years passed. Many scientists have invested their knowledge and experience in studying unusual infections. It did not grow on nutrient media. To confirm his research, Professor of the Department of Clinical Microbiology from the Western University of Australia Barry Marshall conducted an experiment: drank the contents of a cup with the presence of a bacterium. Then, after 10 days, endoscopy showed a connection between the signs of inflammation of the stomach and the presence of Helicobacter.

Marshall and his counterpart Warren did not stop there. They managed to prove the cure of gastritis by the course of Metronidazole and the preparation of bismuth, showed the role of antibiotics in the therapy of gastritis, peptic ulcer of the stomach and duodenum.

Helicobacter has many aggressive properties caused by the internal composition of

. Modern studies have clarified the conditions for the existence of the microorganism. Helicobacter pylori uses for itself the energy of hydrogen molecules released by intestinal bacteria. Synthesizes enzymes:

• oxidase;
• urease;
• catalase.

An important point is being in the stomach in a person with no signs of disease. But in the case of a fall in the protective forces behaves very aggressively, causes inflammation to ulcers and cancerous degeneration. That is why timely detection of traces of Helicobacter pylori by blood analysis is so important for human health.

Who should check blood for Helicobacter?

The introduction of Helicobacter pylori into the wall of the stomach may be accompanied by an atypical, but noteworthy, symptomatology:

• pain - in intensity ranging from weak to strong, occur during or after a meal, there may be "hungry", often a person describes his feelings when passing a food lump through the esophagus;
• heartburn - is associated with the transfer of gastric juice into the lower parts of the esophagus, frequent repetitions are caused by increased acidity and damage to regulatory processes;
• feeling of heaviness in the epigastric region - manifests itself after even ungainly food;
• nausea - no signs of toxicosis of pregnancy or any pathology;
• sometimes vomiting and sharp pains in the stomach, similar to food poisoning;
• presence of mucus and blood in stool;
• constant belching;
• bloating( flatulence);
• violation of bowel movement( constipation or propensity to diarrhea);
• incomprehensible weight loss.

Moderate painful sensations against a background of stressful situations - a sign of infection with helikobacteria

If the listed symptoms are constantly associated with such risk factors as:

• permanent discomfort or overeating, alcohol intake, hunger;
• hereditary unhappiness in the family.

A person should conduct a complete examination to exclude:

• peptic ulcer disease;
• cancer of the stomach or esophagus;
• of esophagitis( inflammation of the esophagus);
• revealing differences with dyspepsia of another etiology;
• gastritis and duodenitis;
• infection with Helicobacteria of close relatives;
• attitudes towards the risk group.

Re-donate blood for analysis is recommended to assess the patient's condition during treatment.

Features of infection of children

The statistics of morbidity shows that 35% of children of preschool age, 75% of schoolchildren are infected with Helicobacteriosis in Russia. Young children get an infection from mothers licking their nipples, a spoon when feeding, from saliva on the background of kisses, common utensils.

Detection of antibodies in the blood allows a timely course of therapy to cure the child. But at the same time it is necessary to look for a bacteriocarrier among adult family members. Since it is established that after 3 years after the course of treatment, 35% of children are re-infected. After a period of 7 years, the number of infected people reaches 90%.

The most common lesion clinic develops in a child:

• from nausea;
• refusal to eat;
• of diarrheal phenomena( profuse regurgitation, bloating);
• of unclear pain.

In what ways can I put Helicobacter pylori through the blood?

The organism of any person reacts to an infectious agent with the development of a protective reaction. In the blood, the level of antibodies increases. They are formed by specific protein complexes and cells. The diagnostic level allows to reveal:

• the presence of antibodies and to give them a quantitative evaluation;
• structure of proteins( immunoglobulins) that are involved in the antigen-antibody reaction;
• DNA cells involved in inflammation.

Appropriately used techniques are called:

• enzyme immunoassay( ELISA);
• assay for antibodies and their protein components( immunoglobulins);
• polymerase chain reaction( PCR) method.

PCR is one of the necessary diagnostic methods for

. How is the enzyme-linked immunosorbent assay performed?

ELISA for Helicobacter is to detect a certain concentration of antibodies in the blood serum. The indicator is evaluated by their dilution or titre. The presence of a positive reaction says that the body reacts with a foreign antigen in the form of helicobacteria. The severity and magnitude of the indicator determine the strength of the response immune response.

Positive aspects of the method:

• possibility of carrying out research at the laboratory level in a polyclinic;
• detection of bacteria in the early stages of infection;
• no need for fibrogastroscopy to confirm the etiology of the disease.

Disadvantages:

• the possibility of a false negative result remains in infected patients if the immunity is not strong enough;
• false positive effect can be obtained in patients already treated, but retained antibodies to Helicobacter pylori;
• itself can not be isolated;
• low titers of antibodies are detected on the background of treatment with cytostatics;
• the results of a study of blood for antibodies to Helicobacter pylori difficult to assess if the patient is treated with antibiotics, even for a case not related to the pathology of the stomach.

Method for studying specific immunoglobulins

Immunoglobulins( Ig) are specific proteins that actively participate in the control of the infectious antigen.

Immunoglobulins are located on the surface of immunity cells, overtake a microorganism anywhere in the body of the

. But they are not produced immediately. In the diagnosis of Helicobacter pylori infection, three types of immunoglobulins are designated: A, M, G. Each plays a role in the inflammatory process:

• IgG is considered a marker that confirms the presence of bacteria in the body, can be detected as early as the third or fourth week after introductioncausative agent, it is important that high figures of the IgG titer remain in humans for several months after the recovery and death of Helicobacter;
• IgM is an indicator of early infection, it is rarely found, the patient still lacks any symptomatology of the inflammatory process, so detection can establish infection in the family;
• IgA - indicates the early stage of infection or a pronounced inflammatory process, it is possible to detect it in the saliva and gastric juice of the infected person, which indicates a high activity and infectiousness of the pathogen.

The positive side of the method can be considered:

• high efficiency of laboratory testing, IgG is detected in 95-100% of patients, IgA - in 67-82% of cases, IgM - 18-20%;
• for blood analysis by comparing immunoglobulin titers with previous indicators, it is possible to monitor abnormalities, the development of a pathological process, the effectiveness of treatment;
• study is more likely than antibodies in the blood to prove infection.

Disadvantages:

• before the appearance of the main marker( IgG) should take a month, this plays into the hands of the delay in diagnosis;
• after cure, especially in elderly patients, the titer remains high for a long time( IgG in half of the patients is found a year and a half);
• is not possible to recognize the acute form of the disease from passive bacteria entering the stomach.

Diagnostic possibilities of PCR method

With the help of polymerase chain reaction in the patient's blood, it is possible to identify DNA bacteria, the basis of the gene composition of the microorganism. Therefore, this method is considered the most reliable. The result is estimated as positive( the bacterium is in the body) or negative( no bacteria in the patient).Confirming the presence of helicobacteria, the method does not provide information on its pathogenicity. It is known that in many people the pathogen does not cause disease.

In addition, when passing the analysis, you need to take into account that no treatment should be performed( not only with antibiotics).This is not achievable, as all patients take any medication to relieve discomfort or pain. The analysis is carried out in specialized centers, so its availability is low.

Preparation for testing and duration of the study

How to take the test, the doctor will tell in detail. The training includes:

• exclusion from food the day before the delivery of blood fatty foods;
• categorical ban on alcohol;
• taking medication should be stopped in 2 weeks;
• minimizing physical activity;
• in the morning of the analysis is not allowed to have breakfast, you can only drink water( from the last meal must pass at least eight hours).

From the taken venous blood by means of precipitation of erythrocytes and other elements a plasma is obtained. The micropipette inserts it into the wells of a special plate with the standard of antigen applied on them. Between substances, in the presence of antibodies in the serum, a reaction occurs and complex compounds are formed, which are visualized by the addition of a coloring compound.

The number of antibodies is judged by the degree of coloration of the

. For a more accurate evaluation of the result, photometry is carried out on the apparatus with a spectrophotometer. It compares the test material with the control samples. Mathematical processing makes it possible to obtain quantitative indicators. The laboratory test for immunoglobulin G is prepared 24 hours, the patient will receive the result the next day. A week is needed to study other globulins.

Decoding of the results of

The expert can correctly decipher the results of the analysis. Doctors usually do not focus on the normal values ​​of Helicobacter pylori and abnormalities. A positive or negative answer is considered sufficient. But the degree of increase in comparison with the norm still indicates the activity of bacterial multiplication in the body.

Sometimes a conclusion is made about a questionable analysis, then it should be repeated after 2 weeks. Each laboratory determines its values ​​(referent) for the norm, they fit into the conclusion form.

Immunoglobulin titers are evaluated in different systems. In units per ml of plasma( U / ml), 0.9 was taken as the norm. Accordingly, normal for immunoglobulins:

• A and G are values ​​less than 0.9;
• M - less than 30.

In the S / CO:

• system, less than 0.9 is considered a negative result;
• 0,9-1,1 - doubtful;
• more than 1,1 - positive.

In the units / ml variant:

• , the negative result is less than 12.5;
• doubtful 12,5-20;
• positive - more than 20.

Negative results of M and G immunoglobulins indicate the absence of infection with Helicobacter pylori, with a negative result of type A, such an inference can not be made, since an early stage of infection is possible.

To estimate the raised level it is possible for immunoglobulins:

• G - presence in an organism of a bacterium or the patient has had been ill and is in the period of convalescence;
• M - infection occurred recently;
• A - the height of the inflammatory process with high activity.

Two weeks after the end of the course of treatment, the immunoglobulin G titer is reduced by half. If its decrease for 6 months has occurred on 2% during, it is possible to hope for complete destruction of helikobaktery. The ratio of the results of suppression of the pathogenic pathogen and the pattern of fibrogastroscopy shows a clear connection with a reduced inflammatory process in the stomach cavity.

Another result: a study in dynamics shows no reduction in titres. Such an effect does not mean wrong treatment, more like a too active process.

Who is contraindicated in the analysis?

Blood from the vein for analysis does not take:

• with the general excitation of the patient;
• on the background of seizures;
• with phlebitis, thrombophlebitis( inflammation) of the vein;
• changes on the skin at the site of the proposed injection.

Contraindications are determined not by the method of investigation, but by the patient's attitude to injections and the condition of peripheral veins on the hands of

. It should not be forgotten that elevated titers of antibodies to helikobacteria are often detected in healthy people. This is due to asymptomatic bacteriocarrier. In such cases, the pathogenic microorganism "lives" in the human stomach and does not harm it.

However, the bacterium carrier can provoke stomach disease in close relatives, children. As it is passed through the dishes, saliva. Whether it is necessary to take a course of treatment to get rid of the bacteria is prescribed by the doctor after examination, clinical examination, study of the risk factors of the patient.

It is not always possible to detect Helicobacter pylori infection by blood. False results confuse diagnosis. Therefore, the methods should be applied in combination taking into account the entire examination of the patient, the capabilities of the laboratory.