Mantoux and Diaskintest: why are tests for tuberculosis needed?

A little about tuberculosis

Tuberculosis has been and remains a dangerous infectious disease. Koch's bacillus, or Mycobacterium tuberculosis, the causative agent of the disease, is so aggressive and resistant to the external environment that it can remain viable for several months in dry sputum, on various surfaces.

Mycobacterium is easily transmitted by airborne droplets (coughing, sneezing) and through household contact. Penetrating into the body, the microbe affects various organ systems, but most often these are the chest organs. However, not in all cases tuberculosis is active - approximately a third of the planet’s inhabitants are “owners” of a latent form of the disease, that is, the microbe is present in their body, but the immune system successfully copes with it. Such people do not suffer from tuberculosis (the possibility of activation of the pathology is no more than 10%) and do not pose a danger to others. If the immune system is weakened (HIV, diabetes, chronic disorders, poor nutrition, stress, and so on), the likelihood of developing the disease increases sharply.

ON A NOTE! According to statistics, the incidence of tuberculosis in Russia has decreased in recent years. However, many experts are skeptical about such data, rightly believing that not all cases of infection and mortality were taken into account. Since the times of the USSR, there has been an opinion that only socially disadvantaged people can get tuberculosis. In fact, mycobacterium does not select a person by status. In addition, this attitude towards the disease leads to a situation where “prosperous” people, having fallen ill, try to hide this fact from others, including doctors and relatives.

Another reason for the lack of statistical recording is the stereotype associated with the symptoms of tuberculosis. It is believed that the patient must certainly choke from coughing, spit phlegm with blood, and so on. But such symptoms indicate an already advanced stage, when the disease is difficult to treat. And at the early stage of infection, a person may only feel fatigue, loss of strength, a slight increase in temperature in the evening and other signs that easily fall into the category of “you just need to rest.” As a result, there is no need to see a doctor, tuberculosis progresses and spreads.

Treatment of the disease is long-term and requires taking medications from different groups for several months. In the absence of timely and adequate therapy, the result is death. In addition, tuberculosis is dangerous due to its complications on the brain, bone tissue and others.

Mantoux – vaccination or test?

Vaccination against tuberculosis - BCG. The vaccine is named after the names of the scientists who created it in capital letters: Bacillus Calmette-Guérin (BCG). The vaccine contains live but inactivated bovine mycobacteria. The first vaccination is given to newborns in the maternity hospital, usually on the 4th day of the child’s life.

Many people do not understand why vaccination is done so early, where can a baby encounter this infection? In fact, the situation with tuberculosis in our country is unfavorable, and not all tuberculosis patients know about their disease. They don’t even suspect that they are contagious and lead a normal life. TB doctors know that the earlier a child is infected, the greater the likelihood of the infection turning into a disease. And the sooner he is vaccinated, the faster the baby will develop immunity and he will be protected. There is even a grotesque poem on this topic, the author of which, unfortunately, is unknown:

“When they come to ask for permission for a child to have BCG done,
And this will be after the birth, but before discharge, Don’t allow it - there are no tuberculosis patients in your family, So that you don’t get infected from others - do your shopping on the Internet, Walk away from all passers-by, visit your girlfriends don't drive, Let your husband quit his job. Warn your relatives that you don’t want to see them anymore for ten years. Kindergarten and school are flying by and warm greetings to the university. Let the child grow up at home, under his mother’s skirt - All wild, unlearned, without life goals or ideas. Old age will creep up unnoticed. He won’t give you water - he’ll go out into the street to get it and get lost there. Alas."

So, in response to vaccination, the body produces protective antibodies - immunity is formed. Immune memory weakens over time, so revaccination is required (repeated administration of the vaccine at seven and 14 years). BCG does not provide 100% protection against tuberculosis, but in case of infection it significantly reduces the risk of complications and death, promotes a milder course of the disease and a faster recovery.

Mantoux allows you to:

• determine the body’s sensitivity to mycobacteria;
• identify the hidden form of the disease;
• assess the risk of developing the disease in the future.

In other words, using the test, you can not only detect tuberculosis in a timely manner, but also predict the immune response to infection.

What's included

The drug contains a complex mixture of mycobacterial proteins - tuberculin. It is pre-cleaned and treated with special solutions. It does not pose a danger to human health and is not a cause of tuberculosis.

FROM THE HISTORY. Tuberculin was discovered by the German microbiologist R. Koch in 1890 for the treatment of tuberculosis. The crude composition led to numerous and severe toxic effects, recovery did not occur, so it was perceived critically by society. But as tuberculin was further used in animals, the diagnostic properties of the drug were discovered. In 1907, a scientist from Austria, K. Pirke, proposed using tuberculin diagnostics for people using a skin test. And in 1908, C. Mantoux (France) developed a method of intradermal administration, which is used in diagnostic practice to this day. The purified preparation was adopted by WHO as an international standard in 1952.

What is Diaskintest

"Diaskintest" is a domestically produced drug intended for the diagnosis of tuberculosis. It is administered in the same way as Mantoux - intradermally into the forearm area. Diaskintest was introduced into Russian clinical practice in 2009.

As in the case of Mantoux, a conclusion about the presence/absence of a disease is made based on the body’s reaction. The formation of a compaction of a certain size at the injection site indicates infection with Koch's bacillus. Diaskintest has high specificity and sensitivity: it can detect the causative agent of tuberculosis in 96% of cases. For comparison, Mantoux gives a positive reaction to vaccine mycobacteria (BCG) and other non-tuberculosis strains of microorganisms.

ATTENTION! Diaskintest is not an alternative to Mantoux! This is a clarifying method for diagnosing tuberculosis. It can also serve as an assessment of disease activity during treatment and the effectiveness of the therapy.

Diaskintest is suitable for people of any age. A negative result will show with very high confidence that the person is not infected with mycobacteria.

For the differential diagnosis of tuberculosis and other diseases, a test with the drug Diaskintest is carried out in combination with a clinical, laboratory and x-ray examination in an anti-tuberculosis institution.

What does the drug contain?

The drug "Diaskintest" is a product of genetic engineering. This is a protein obtained artificially. It includes two antigens - compounds foreign to our body, which are characteristic specifically of the causative agent of tuberculosis. Therefore, the drug causes a reaction only if there are mycobacterium tuberculosis in the body. Like Mantoux, Diaskintest does not contain mycobacteria in any form and does not contribute to infection.

Evaluation of results

As mentioned above, manipulations are performed on different hands. Three days later, the specialist evaluates the results and draws appropriate conclusions, taking into account Mantoux and Diaskintest. It is important to adhere to all post-vaccination rules so that the information is truthful. If the child wets the injection site, you need to tell the doctor about it.

A specialist always evaluates the size of the papule. Depending on this, a verdict is made.

Mantoux is positive and Diaskitest is negative

If the Mantoux is positive and the Diaskintest is negative, it means that the child has immunity after BCG. It is also assumed that there is MBC in the body, but they do not differ in their activity. To verify and clarify the result, it is advisable to re-test after a certain time. If parents do not want to wait, they seek advice from a TB specialist, who in turn prescribes additional diagnostics. If a disease is detected, treatment must begin.

There is also a variant of positive Mantoux - contact of the corresponding hand with water. It is important not to wet or treat the injection site with any antiseptic. If any actions were performed, the doctor will not be able to reliably assess how the body reacts to the vaccine.

With a negative Diaskintest, tuberculosis is rarely detected in humans, since this is a fairly reliable and effective diagnostic method.

Mantoux is negative and Diaskitest is positive

If the Mantoux reaction is negative, and the Diaskintest gave a positive result, the information here can be assessed in the same way as in the situation described above.

Most often, this manifestation indicates the presence of Koch's bacillus in the body. To confirm this, other diagnostic procedures are done. If the body is not infected, then there should be nothing on the hand where Diaskintest was done, since the antigen protein does not react to anything other than mycobacteria.

Mantoux positive and Diaskitest positive

There is undoubtedly an infection with the tuberculosis bacillus. Positive reactions on both hands are a reason to start immediate treatment. You must first visit a phthisiatrician and undergo other diagnostic measures. The latter usually determine the degree of infection and the form of tuberculosis.

If the condition is extremely serious, hospitalization cannot be avoided. Only health workers are able to provide all the necessary assistance to the patient. After this, the patient is usually transferred to outpatient treatment, where he continues to take the prescribed medications. In the future, you should plan a sanatorium-resort treatment that will consolidate the result and prevent the disease from worsening.

Mantoux negative and Diaskintest negative

If there are no papules and redness on the hands, this indicates negative results of both Mantoux and Diaskintest. This reaction indicates that the person has not had contact with mycobacteria, and there is no need to worry about anything. No further examination is required.

Next time, it is not recommended to do simultaneous diagnostics, as this is a lot of stress for the body.

The injection site may change due to other factors that have nothing to do with tuberculosis infection, these are:

1. Allergic reaction to the components of the drug. In this case, swelling, rashes, ulcers, extensive hyperemia appear, and even body temperature rises. In severe cases, breathing difficulties are observed. To prevent the occurrence of anaphylactic shock and other equally dangerous manifestations, you should immediately go to the hospital. If the doctor sees something similar on the arm, this means that the child is contraindicated for further examination for tuberculosis in this way.
2. Failure to comply with the rules in the post-vaccination period. Papule and redness sometimes occur if the hand is wet or treated with alcohol solutions, ointments or gels. Contact with any product is strictly prohibited. This can lead not only to a false positive result, but to various consequences.
3. Incorrect administration of the drug. If the manipulation was carried out by an unqualified specialist, then a false result may also appear. To avoid such an excess, you must first make sure that the nurse has enough experience in performing such injections (if, of course, such a possibility exists).
4. Carrying out tests and samples during a respiratory illness or an exacerbated chronic disease. If the child was not examined beforehand, or the doctor did not pay attention to the fact that he was sick, the immune system may not cope with the drug and react to it in all possible ways, not in favor of the patient. Naturally, after this, the current disease will take much longer to heal and the test itself will be false. As a result, you will have to re-diagnose.

In any case, only a doctor can decipher the result of one or another test.

Comparison of Mantoux and Diaskintest

Immunodiagnosis using Mantoux is carried out for children vaccinated against tuberculosis from 12 months of age until they reach the age of 18 years. An intradermal allergy test with tuberculin (Mantoux test) is performed once a year, regardless of the results of previous tests up to and including 7 years of age.

Diaskintest is performed once a year, regardless of the results of previous tests from 8 years of age to 17 years of age inclusive.

For those not vaccinated against tuberculosis, a Mantoux test is performed 2 times a year, starting from the age of 6 months.

Below is a comparative table of the Mantoux and Diaskintest tests.

If the result is positive or questionable, in both cases additional examination is required. This may be a laboratory test of blood, sputum or smear, chest x-ray, CT, MRI and other methods.

Reasons for joint holding

Why is the Mantoux test and Diaskintest done at the same time? Since these two diagnostic procedures differ in their effect, outcome indicators will provide the opportunity to obtain more accurate information.

Such an examination is advisable if the parents are sure that the child was in contact with a tuberculosis patient. The sample and test can detect pathology even at an early stage. An active form of tuberculosis can also be detected.

If the father and mother cannot decide what to choose, in this case (in the absence of contraindications and the presence of strong immunity), the doctor may advise doing both.