Let's start with what this test is made for and what it is all about. Tuberculin is introduced into the body and a reaction to the administration of this drug is observed. This is the only way to determine the predisposition of the child's body to this dangerous disease. The reaction of the body can be called a type of allergy. In the place where the drug was administered, redness should occur - a kind of inflammation caused by blood cells that are responsible for immunity at the cellular level. What does the term “positive reaction” mean? Inflammation exceeds that caused by the injection itself. Redness (papule) is measured with a ruler. The diameter determines whether the reaction is positive, or Mantoux is the norm. By the way, tuberculin itself is not an antigen, it is rather an allergen.
How is the Mantoux norm estimated in children? Two to three days after the administration of the drug, a specific rounded, reddened seal appears on the skin. Evaluation is carried out after 72 hours, starting with an external examination. In this case, it is possible to establish both the absence of a reaction in general, and hyperemia, or infiltration. It is important to distinguish hyperemia from infiltrate. Palporno determined the thickness of the skin folds over the area of healthy skin, then at the injection site. The skin fold with infiltration thickens, as in a healthy area, the same. Then comes the measurement and registration of the size of the infiltrate. To do this, you need a millimeter transparent ruler. "Materials at hand" for this purpose are unacceptable. Be sure to track how the evaluation of the test result will be carried out. It should be done in a bright room, only with a transparent ruler and only by a specialist! Only the size of the seal is subject to measurement. Reddened skin near the seal is a sign of immunity, or infection is not.
Now in more detail about what it means: "Mantoux is the norm." The sample is considered negative with a completely absent papule and an injection prick from 0 to 1 mm. With such indicators, Mantoux is the norm. If the size of the infiltrate is from 2 to 4 mm, with redness and increased blood supply to the tissue, the sample is considered doubtful. In the case when the infiltrate is 5 mm or more, the reaction is positive. This is a cause for alarm, but not for panic, since the test does not serve as evidence of tuberculosis. The following points testify to danger:
- annual increase in sensitivity to the sample;
- a sharp jump with an increase of 6 mm or more;
- stay in the zone of increased circulation of tuberculosis (even short-term);
- contact with a patient with tuberculosis (even short).
In these cases, the child should be referred to a TB specialist.
The reaction is considered weakly positive at an infiltrate size of 5 to 9 mm;
average intensity - from 10 to 14 mm; pronounced - from 14 to 16 mm, hyperergic 17 mm and more.
In a young child in two or three years, a positive reaction to the introduction of tuberculin may well be a post-vaccination allergy. The reaction depends on the individual reactivity and in a year and a half after BCG it can be negative, and doubtful, and positive (by the way, the latter is observed in 60 cases out of a hundred, according to statistics). As a post-vaccination allergy, positive reactions develop after 6 weeks, they reach a special intensity by two years, when the period of post-vaccination immunity is especially pronounced. Therefore, in the first year or two of a child’s life, reactions to a test can “show” 5-16 mm. and a 4 mm BCG scar indicates post-vaccination immunity up to three to four years. Mantoux is recommended for such children against the background of desensitizing agents (5 days before, 2 days after). If the result is positive, a visit to a TB doctor is mandatory. It is important to exclude any possible factors: infection, allergy, etc. If, nevertheless, the reaction has caused allergies, the child is most often sent to the PDD for examination, putting on record. Six months later, the sample is checked. With an increase in the size of the reaction (or at the same size), the allergy is considered infectious. Reduced sensitivity suggests an allergy to post-vaccination.
It’s good when Mantoux is the norm. But with other indicators, panic is still not worth it. As a rule, additional examinations dot the "" and ", refuting the presence of tuberculosis in the child's body.