Analysis for Helicobacter pylori
Helicobacter pylori is a bacterium that normally lives in the gastrointestinal tract of many people. Under favorable conditions, the colonies of Helicobacter pylori increase, causing pathologies of the stomach and intestines. Before prescribing a course of treatment, the doctor must make sure of the presence of pathogenic microorganisms in the gastrointestinal tract, clarify the level of their concentration.
An analysis for Helicobacter pylori is prescribed for painful sensations and discomfort in the stomach before eating. Helicobacter pylori infection provokes the development of serious lesions of the mucous membranes. Timely detection of the infection and its elimination help to avoid the development of serious cancers and other health disorders.
This analysis gives a general idea of the causative agent of the infection, since it is currently considered one of the most accurate. The presented spiral microorganisms often live in the lower stomach, as well as in the duodenum. Such anaerobic microbes are instantly killed in the air. Often, the disease is transmitted from an infected person to a healthy person through mucus and saliva, as well as through the household. Once in a new organism, bacteria descend directly into the stomach.
The hydrochloric acid contained in the stomach does not destroy this type of microorganisms. Bacteria burrow into the mucous membranes of the stomach, easily disrupting the structure of the tissues, which leads to defective functioning. This potential hazard causes severe inflammation, erosion and ulceration. In addition, Helicobacter pylori is able to change the local acidity of the stomach.
These microorganisms easily spread throughout the stomach with weakened human immunity and with a long existence.
Timely diagnosis avoids many dangerous consequences. For any symptoms of gastric malaise, a specialist will prescribe an analysis for Helicobacter pylori. Many patients complain of problems in the digestive system. These include recurrent acute pain in the stomach, the appearance of heartburn, a feeling of heaviness and rejection of fatty meat foods. As a rule, with Helicobacter pylori, severe pain disappears immediately after eating.
Content:
- Indications for testing
- Preparation for analysis
- Types of analyzes and diagnostics
- Interpretation of analysis results
- Antibodies IgG to Helicobacter pylori
- If Helicobacter pylori is positive - what does it mean?
- The results of the analysis of feces for Helicobacter pylori
- Determination of Helicobacter pylori antigen in feces
- Helicobacter pylori IgM and IgA - what is it?
Indications for testing
It is difficult to imagine that a person without symptoms of the disease went for a full-scale examination unnecessarily.
Symptoms predisposing to testing for Helicobacter pylori:
- Gastralgia (pain in the stomach and intestines) of varying intensity. They appear during or after eating, caused by a deficiency of enzymes and impaired digestion of food and its congestion in the stomach.
- "Hungry pains." Appear 2-3 hours after eating, stop while eating. Due to damage to the mucous membrane, its sensitivity is aggravated, the patient feels how food and water pass through the digestive tract.
- Intense heartburn. It occurs due to the reverse reflux of aggressive gastric juice into the esophagus not intended for this, with frequent repetitions it is a symptom of pathology.
- Feeling of heaviness that occurs even after taking minimal portions of food. The patient has a feeling of a full stomach.
- Frequent nausea, not caused by objective reasons (for example, pregnancy toxicosis).
- Combination of stomach pain with vomiting and inability to eat and drink.
- Slight discomfort in the projection of the stomach, loss of appetite, slight heaviness. They often appear at the initial stage of heliobacteriosis.
- The presence of mucus in the stool.
Any of these symptoms is a reason for an immediate visit to a doctor for examination and treatment.
Preparation for analysis
To obtain objective indicators, you need to carefully prepare for the delivery of tests for Helicobacter pylori.
Necessary preparatory measures:
- Complete cessation of smoking a day before testing. Nicotine negatively affects the gastric mucosa, distorting the test results.
- Complete rejection of alcohol. The reason is the same.
- Prohibition of drinking tea and coffee, which negatively affect the state of the gastrointestinal tract.
- Temporary restriction on food intake within 8 hours before analysis.
Since the blood for the analysis for Helicobacter is taken from a vein on an empty stomach, you can take some food and water with you to the clinic.
Types of analyzes and diagnostics
There are several methods for studying the state of the body. Each of them has its own characteristics.
ELISA for bacteria
An enzyme-linked immunosorbent assay is prescribed to assess the level of concentration of antibodies to Helicobacter pylori in the patient's blood. If there are antibodies to the bacteria in the blood, it means that the immune system developed them at least 1-2 weeks ago. If the body's reaction has not yet been formed, a false negative result is possible.
Reasons for false positive results:
- mistake of the laboratory assistant who conducted the study;
- not enough time has passed after eradication, since antibodies are in the blood some time after a complete cure.
A positive ELISA result indicates the need for a complete examination, studying the results of an extended blood test, which gives more information about the state of the body.
Immunoglobulins in the blood LgG, LgM, LgA
In the human body, when infections or pathogenic microorganisms enter it, immunoglobulins are produced - proteins of blood cells that resist foreign viruses. When infected with heliobacteriosis, the human body produces immunoglobulins LgG, LgM, LgA, which actively oppose Helicobacter pylori. If they are found in a person's blood, it should be concluded that he is sick with heliobacteriosis.
The peculiarity of immunoglobulins is that in pursuit of pathogenic cells, they overtake them anywhere in the human body. These proteins are produced after the digestion of bacteria in the gastrointestinal tract.
Analysis of analyzes:
- A reduced or negative level of immunoglobulin LgG indicates one of the following options: the bacterium is absent in the body and the likelihood of developing a peptic ulcer is low, or only 3-4 weeks have passed since infection. In case of pain in the gastrointestinal tract, you need to repeat the examination in a week.
- An elevated or positive level of immunoglobulin LgG indicates one of two options: the bacterium is present in the body, increasing the risk of developing cancer and stomach ulcers, or the person has recently been cured of heliobacteriosis.
- A decreased level of immunoglobulin LgM, usually detected immediately after infection, or its absence, clearly indicates the absence of bacteria, since this protein is found early after infection.
- An increase in the LgM level indicates that the gastrointestinal tract is at an early stage of infection, and it is almost intact by infection.
PCR analysis
The results of the polymerase chain reaction study can fix Helicobacter pylori DNA samples in the blood, which puts the PCR test in the first place among all diagnostic methods. A positive test result proves the presence of bacteria in the body, negative - its absence. The only thing that is not available when performing a blood test for PCR is determining the time of introduction of the bacteria into the body.
If antibiotic therapy or antiseptic treatment was carried out before taking blood for analysis, the results of the study will not be objective. It is better to entrust the decoding of blood tests to a specialist, although serious laboratories put a table of norms and deviations from it in the results.
Cytological examination
In this test, swabs are taken from the mucous membrane of the antrum during endoscopy. The smear area is the site of edema and hyperemia, but not erosion or ulcers. After taking the prints, the laboratory technician dries and stains the smears.
When examined under a microscope, Helicobacter pylori can be found in the form of a spiral or in the form of the wings of a flying gull.
Reference values for cytology:
- (+) - low level of contamination (up to 20 microbial bodies);
- (++) - average level (up to 40 microbial bodies);
- (+++) - high level (over 40 microbial bodies at 360x magnification).
Additionally, in the presence of inflammation, cellular infiltration is detected: (eosinophilia, neutrophilia, lymphocytes, plasma cells). Additionally, you can find dysplasia, proliferation, metaplasia, malignant neoplasms.
Urease test
The examination is performed after taking a biopsy of the mucosa during endoscopy. It is placed in a carrier gel containing urea, pH indicator, bacteriostatic agent. Conclusions are made based on the color change of the biopsy specimen in the range from yellow to crimson.
Reference values:
- Raspberry color appeared in the first hour - severe infection (+++);
- In the first 2 hours - a moderate level of infection (++);
- By the end of the day - an insignificant level of infection (+);
- At a later date, the norm or negative result.
With a low level of infection, a false negative result can be recorded. To increase the reliability, it is combined with a histological method.
13C urease test, respiratory
During this test, background breath samples should be taken on an empty stomach. After a light breakfast in the form of juice or milk, the subject drinks an aqueous solution of urea labeled with 13C, the so-called test solution. Then, every 15 minutes, 4 final samples are taken.
Analysis of the test based on the presence of a stabilized isotope using a mass spectrometer:
- Mild infection - less than 3.5%;
- Average degree - 3.5-6.4%;
- Severe degree - 6.5-9.4%;
- Very severe degree - over 9.5%.
The rate of Helicobacter pylori in the urease test is 1%.
Hemotest
The analysis is based on the determination of the titer of antibodies - class G immunoglobulins. Normally, when Helicobacter enters the body, they bind microorganisms, stopping their pathogenic effect. The study is carried out by enzyme immunoassay after taking blood from a vein into a sterile test tube. Before the examination, one should not eat for 8 hours, drink coffee and alcohol, or smoke. To study the dynamics, the analysis is carried out throughout the entire period of treatment.
Interpretation of analysis results
Despite the fact that the decoding of the indicators must be entrusted to the doctor who sent them for examination, all patients want to find out their results on their own.
How much is the norm of Helicobacter pylori? The norm for bacteria in venous blood testing: <0.9 U / ml.
Interpretation of other meanings:
- 0.9-1.1 U / ml - the likelihood of Helicobacter pylori infection is doubtful;
- More than 1.1 U / ml - bacteria are definitely present in the body. High risk of developing stomach ulcers and stomach cancer.
The norm for the urease test is the absence of a crimson color in the color of the material. The norm for bacterioscopic examination is the absence of pathogens.
Antibodies IgG to Helicobacter pylori
Detection of immunoglobulins to Helicobacter pylori is carried out using the enzyme-linked immunosorbent assay, or "sandwich" method. For research, venous blood is used; before it is donated, you must not smoke for 30 minutes.
The method is based on the fact that after the Helicobacter bacteria enters the body, a local and systemic response develops. It consists in an increase in the titer of immunoglobulin IgM, IgG-, IgA-antibodies in the blood serum. In 100% of cases of infection, IgG-immunoglobulin is detected, in 65-80% of cases - IgA, in 17-20% - IgM, therefore, accurate diagnosis is carried out by determining the concentration of IgG in the blood serum.
The advantages of the method:
- Does not require endoscopy, so the method is safe;
- Highly sensitive;
- Used to prevent primary infection.
The method may be inaccurate in determining the titer of immunoglobulin in the elderly, since they have a reduced production of antibodies, as well as in those patients who take cytostatics. After the treatment of heliobacteriosis, this method is also not effective, because the level of the hormone in the blood after treatment with antibiotics remains quite high for another 6 months.
Indications for use:
- Patient complaints of dyspepsia if it is impossible to carry out endoscopy;
- Primary diagnosis of heliobacteriosis;
- Monitoring the effectiveness of antibacterial treatment.
The reference values of the survey: the concentration of IgG-immunoglobulin is from 0 to 0.9, the result is negative. This may mean that there is no infection or that the therapy is highly effective.
If Helicobacter pylori is positive - what does it mean?
A positive test result proves the presence of bacteria in the body, negative - its absence. Not always positive indicators indicate a disease with heliobacteriosis. Most often, this is a sign of the presence of bacteria in the body. However, immediately after the eradication of Helicobacter pylori, the analysis for its content in the body will still be positive, despite the absence of bacteria - antibodies in the blood do not disappear quickly. It is they who give a false positive result, so the analysis should be taken no earlier than a month after treatment.
This is the only exception to the rule: a positive result for Helicobacter means the presence of the disease or the carrier of the bacteria.
The results of the analysis of feces for Helicobacter pylori
After studying the material provided by the patient, you can absolutely accurately answer the question of whether there is Helicobacter pylori in his body, or not, that is, the analysis of feces is of high quality.
Determination of Helicobacter pylori antigen in feces
The study is performed by the method of polymerase chain reaction (PCR). Its accuracy is 95%, the determination of the presence of bacteria in this way is recommended in children, in elderly and seriously ill patients.
For the result of the analysis to be objective, you need to prepare for the study:
- Do not take antibiotics for 4 weeks before the study;
- 3 days before the study, do not eat foods that color feces: red grape wine, beets, grapes, black currants;
- Before the study, exclude products with coarse fiber from the menu in 2-3 days: bran, radish, cabbage, carrots, beets;
- Do not use drugs that increase gastrointestinal peristalsis.
For research, it is enough to fill one third of a standard container for collecting analyzes. Do not take feces from the toilet, as it may carry traces of detergent. It is advisable to store the container with biomaterial no longer than 10-12 hours at temperatures from +2 to -8 ° C.
The analysis result can be obtained the next day. Because stool analysis is a qualitative study, the result is reported as “positive” or “negative”.
Helicobacter pylori IgM and IgA - what is it?
Immunoglobulins of class M are blood proteins that, earlier than other immune fractions, react to the appearance of Helicobacter bacteria in the body; they can be fixed in the blood at an early stage.
- A positive test result for the presence of IgM immunoglobulin occurs when the titer of antibodies rises during infection with heliobacteriosis;
- Positive indicators of IgA content are an indicator of the active process of the introduction of bacteria into the gastric mucosa and its inflammation.
In a healthy person, these indicators are absent or present in minimal quantities.
Author of the article: Danilova Tatyana Vyacheslavovna | Infectionist
Education: in 2008 received a diploma in General Medicine (General Medicine) at the Pirogov Russian Research Medical University. Immediately passed an internship and received a diploma of a therapist
