The diagnosis of tuberculosis is being improved more and more. The old methods are being replaced by new, more accurate and perfect ones. These include diaskintest.
What it is?
Diaskintest is a reaction somewhat similar to the Mantoux test, but more sensitive to human tuberculosis mycobacteria. Like the Mantoux reaction, it is used mainly in children, although in some cases it is also indicated for adults.
The technique has gained distribution relatively recently. The incentive for its creation was the fact that the Mantoux reaction did not provide accurate information as to which antibodies to which strain of mycobacteria are present in the body (since it determines the sensitivity to two subspecies - human and bovine mycobacteria).
The specificity of the injection is almost 90 percent, while the sensitivity of the sample with tuberculin does not exceed 50. Because of this, the occurrence of false and incorrect results is high.
You should understand how the diaskintest is carried out, and also determine the contingent to which this reaction is shown.
How is the procedure performed?
The diaskintest itself, reviews of which are currently mostly positive, is no different in methodology from the Mantoux reaction. A sample is taken on the inside of the forearm. The needle is inserted intradermally by a few millimeters. After administration of the drug, a papule with a surface of the type of "lemon peel" is formed at the injection site. After some time (usually after two days), an assessment of the formed papule is carried out.
Diaskintest for tuberculosis must be carried out in specially equipped rooms or treatment rooms. It is forbidden to carry out an injection at home, as well as by untrained personnel without the created conditions of sterility. This can lead to complications after the procedure.
To determine the results of the study, changes in the area where the diaskintest was performed are evaluated.
Assessment of the test results is carried out according to certain criteria. Upon receipt of a negative result (not one of the criteria has been identified), the study is repeated or sent for further examination to specialized institutions.
What signs are used to evaluate the effectiveness of the procedure and health status?
Criteria for evaluation
After the diaskintest was carried out, the evaluation of the results is carried out according to the presence of changes in the injection zone.
Normally, a hyperemia zone should form at the injection site. Its appearance is due to an increased blood flow to the injection site, as well as a local allergic reaction.
The size of the papule depends on the degree of the immune response. The larger the diameter of the formed papule, the stronger the response of the immune system. However, too small or, conversely, an excessively large papule size are unfavorable signs, since they indicate a weakened or overly active immune system and its response to the introduction of foreign antigens.
In addition, the formed papule is compared with previous results, determining the dynamics of changes. If there is a positive reaction to diaskintest, the photo and size of the papule are necessarily compared with previous results. It is possible that over a given period of time (the year since the last reaction), a person has had contact with a patient with tuberculosis. In this case, a comparison with past results is required.
Diaskintest for tuberculosis is considered to be carried out in accordance with all the rules and standards if there are two of the above criteria.
Interpretation of Results
How can we judge the presence of antibodies to mycobacteria?
Diaskintest is evaluated according to two criteria - redness in the injection area and size.
If there is no hyperemia zone at the injection site, this indicates that either the procedure was carried out incorrectly or the immunity is so weak that it cannot respond to the introduction of antigens. This is also indicated by the absence of a papule at the injection site.
If there is hyperemia, and the papule is small (up to 4 mm), a weak immune system is judged. A similar result may indicate that there are very few antibodies, and the body will not be able to cope with it when mycobacteria get into it.
What is the result of a healthy person on diaskintest? Its norm is from 4 to 12 mm, which indicates the normal function of the immune system and the presence of the necessary antibodies.
If suddenly a papule larger than 12 mm is formed at the injection site, this indicates a hyperreactivity of the immune system, i.e. an allergic reaction may develop in response to the penetration of mycobacteria.
However, it should be remembered that the results in adults and in children may differ slightly from each other. In adults who were given a diaskintest, the norm will be slightly larger - from 4 to 16 mm. This phenomenon is observed due to the fact that in an adult human body there are more antibodies than in a child. Some of them can be activated in the presence of antigenic mimicry - the mycobacterium antigen can be recognized as a foreign protein of another microorganism, and other cells may be activated in response to this, which will slightly increase the allergic reaction.
Sometimes the absence of a papule or its large size may indicate that the procedure was carried out incorrectly. Be sure to conduct another to clarify. If the result is repeated (repeated negative or positive diaskintest), a consultation with a TB specialist is indicated.
Surveyed contingent
To whom is this procedure indicated?
Be sure this study is conducted for children under 17 years of age. This is because the main method of screening for tuberculosis - fluorography - is associated with x-ray radiation, which can affect the development of the child's body. That is why preference is given to the introduction of antigens rather than radiation.
The injection is given to children about six months after the introduction of the BCG vaccine. During this time, antibodies to mycobacterial antigens have time to form, which makes the study expedient.
In addition, a procedure should be performed for people registered with the endocrinologist about diabetes.
Without exception, everyone undergoes a diaskintest in the presence of significant changes in the papule compared to the previous study (the procedure is performed once a year, but unscheduled research can be performed up to 3 times).
A positive diaskintest is often determined in people serving sentences (in prisons, colonies), so they are examined several times a year.
Indications
Diaskintest, like the Mantoux reaction, is a purely diagnostic procedure aimed at mass monitoring of the development of tuberculosis in childhood.
Usually this study is carried out as planned, but there are some indications for its extraordinary conduct.
As such predisposing factors are the turn of the Mantoux reaction, a significant change in the formed papule compared to previous results. In children with prolonged (more than a month) subfebrile condition and the presence of dry cough, a follow-up examination, including a diaskintest, should be carried out. A photo of the chest organs (fluorogram) in this case is done with the permission of the child's parents and is used to clarify the diagnosis.
In addition, the study is mandatory for children and adults suffering from diabetes (since this disease provokes the development of immunodeficiency, facilitates the penetration of the pathogen into the body and the development of the infectious process).
An unscheduled test is mandatory for children whose parents have been diagnosed with tuberculosis.
Contraindications
Like any procedure, diaskintest has some contraindications. These include increased sensitivity to the constituent components of the drug, as well as the presence of an active infectious process in the study area (diaskintest is somewhat limited in application, since the injection is carried out on the forearm, where the skin is quite thin, which allows the formation of papules. There is no other area of the body on the skin always able to get the necessary results).
There is also some age restriction. The procedure is not performed for newborns and children who have not previously received BCG vaccination.
With caution, the study is conducted for people with immunodeficiency, since the introduction of antigens can provoke an incorrect response of the body.
Diaskintest Benefits
As you know, diaskintest replaced the Mantoux reaction. This was due to the fact that the Mantoux reaction does not give accurate results regarding antibody formation against human tuberculosis mycobacteria (determines the presence of antibodies against two strains of mycobacteria). Diaskintest, the reviews of TB doctors about which are mostly positive, is a more narrowly targeted procedure, since the drug administered contains only antibodies m. Tuberculosis.
Isolated cases are known when, after injection, active tuberculosis developed during the Mantoux reaction. In epidemiological terms, diaskintest is safer, since it does not contain active mycobacteria, but only their antigens that contribute to antibody formation. A hypersensitivity reaction almost never develops with the introduction of the drug.
Since the procedure is no different from the standard tuberculin diagnostics, most trained procedural sisters can conduct it.
Opinions of patients and doctors
For the short time that diaskintest is used, he received a considerable number of reviews from both patients and doctors.
When studying the majority of forums where patients, tuberculosis patients, or their relatives who have undergone diaskintest communicate, reviews in most cases were positive. According to people, the procedure is quite simple to implement, does not require any training from them.
What do doctors think about this? Many TB doctors are inclined to believe that diaskintest is a more universal procedure than the Mantoux test or Pirke cutaneous test (currently not used). The high specificity of the drug allows with almost one hundred percent confidence to confirm the presence of mycobacteria in the body and start treatment in a timely manner. Many agitate patients to give preference not to a fluorogram (which allows only the disease to be detected), but to undergo a diaskintest. Reviews of doctors about the procedure are almost always positive, only a small part of them prefer radiography or Mantoux.
Where can I go through the procedure?
If you suspect that you have tuberculosis, the question often arises of where to go. Such thoughts usually appear after the radiologist noticed a shadow in the picture of the lung, or you cough for a long time, feel weak and bruised. All this indicates the possible presence of active tuberculosis, and you can not hesitate with the diagnosis.
First of all, diaskintest can be passed in specialized institutions - tuberculosis dispensaries or clinics. Typically, the procedure is performed by everyone for a fee, although you can and even need to go there and in the direction from the local therapist.
In addition, for this procedure, you can contact the regional health centers (for example, district hospitals) or the health service. Usually, there should be at least one TB specialist in the area who can correctly examine you and, if necessary, diagnose tuberculosis with the help of a diaskintest.