4.5.1.1. Tuberculin diagnostics (Mantoux test)

Content

• At what age are children tested for the Mantoux test?
• What does the reaction to a tuberculin test look like?
• Mantoux vaccination: after how many days is it checked?
• Is it possible to test Mantu on day 4
• How to test Mantoux for tuberculosis

The Mantoux test is an intradermal or cutaneous test that is performed to identify the specific response of the immune system to the introduction of tuberculin. Thus, it is not intended to develop immunity to the disease in the baby, like other vaccinations, but to identify immunity to tuberculosis. The tuberculin test (the second name for the Mantoux reaction) is a very important diagnostic procedure for every child. The reaction to the test is checked by a doctor several days after the procedure. Many parents, worried about the health of their baby, want to know the preliminary result even before being examined by a doctor. In this article we will tell you on what day Mantu is checked and how to do it yourself. It is important to remember: independent “diagnosis” in no case can replace an examination by a professional.

When to check Mantoux

The Mantoux reaction, although not a vaccination in the full sense of the word, is included in the list of mandatory vaccinations that a child must receive. For the first time, a tuberculin test is performed on one-year-old babies. If the procedure is performed earlier, due to possible skin reactions, it is difficult to determine the result.

Then the Mantoux reaction is checked every year at approximately the same time until the child turns 14 years old. Children who have not been vaccinated against tuberculosis are given a Mantoux test twice a year. And for children who are at risk, i.e., who have close contact with a person with tuberculosis, the Mantoux reaction is checked 2-4 times a year. The Mantoux reaction is checked after a few days by doctors.

After tuberculin is injected intradermally into the child, bacterial particles begin to attract T-lymphocytes. Thus, T-lymphocytes that have already dealt with Koch’s bacillus react to the introduction of the substance. This is the Mantoux reaction, which externally looks like a compaction, a “button” on the inner surface of the forearm. It must be of a certain size and shape; if there are deviations, the doctor may suspect tuberculosis in the child. In order not to sound the alarm ahead of time, scaring yourself and your child, it is important to know after how many days Mantoux is checked. During the first days, the injection site may become red and inflamed, and may be too swollen, making examination difficult.

The substance tuberculin itself, which is used to test, is not capable of causing tuberculosis. It consists of weakened tuberculosis pathogens and is not dangerous to humans.

Educational program for parents about mantu

A mantu test is given to a child to determine the reaction of his body to tuberculosis bacilli. Tuberculin is injected into the subcutaneous layers of the hand (the place between the wrist and elbow on the inside) - harmless remnants of the very rods that cause this disease. If extensive redness with compaction forms at the vaccination site, the reaction is considered positive and the child is taken under control.

Many people believe that if during these three days they accidentally wet the vaccination site, this is exactly the reaction that will follow. As a result, the poor child will be dragged to the doctors, will have to go to a tuberculosis dispensary, teeming with infectious patients, and have a far from harmless X-ray. In fact, we are in a hurry to pleasantly surprise parents and reassure them: manta rays can be wetted, and this will not affect the body’s reaction to the vaccine at all. How so? A few facts will convince you of this.

1. The first completely logical question that arises when familiar with such a statement: why do our competent pediatricians warn that manta rays should not be wetted? The fact is that until the late 60s and early 70s of the last century, instead of the subcutaneous Mantoux test, a completely different procedure was used - a cutaneous one, which even had a different name, the Pirquet test. Its essence is that a tuberculin solution was first dripped onto the child’s hand, then scratches (notches) were made directly through the drops of the solution. This sample actually could not be wetted, since the allergen (tuberculin) could be washed out of the scratches, and the result in this case could be incorrect. The test and the procedure itself have changed, but the stereotype of medical thought remains to this day. So literate parents can now check the professionalism of the doctor who gives their child mantu and ask him whether it is possible to wet the puncture site.
2. To prove that there is nothing wrong with the fact that you accidentally wet manta rays for your child, here is one more fact. The modern test is intradermal. Tuberculin is injected deep under the skin with a thin, long needle. The drug instantly disperses throughout the body. How can water affect this drug? No way. Water procedures do not affect the redness of the place where the vaccination was given.

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If doctors in schools, kindergartens, and clinics provided information education to parents about their child’s reaction to the mantoux test, they could save many suspicious mothers from completely unnecessary worries. After all, the only answer to their question of what to do if they accidentally wet a manta ray on a child’s hand is to calm down and not worry.

If possible, you need to protect a child who has received mantu from contact with allergens.

How long does it take to check Mantoux on a child?

The reliability of the results obtained depends directly on what day the manta ray is tested. A reliable result will be detected after 72-76 hours, i.e., after three days. The correct result will be only during this period. After these hours, the size of the “button” changes and the diagnosis will be incorrect.

The doctor who checks Mantoux uses a special medical ruler to measure the size of the papule. The smaller it is, the better. The norm for a healthy child is 0-1 mm. But it is worth remembering that sometimes a tuberculin test can give a false result - positive or negative. The reason may lie in other diseases of the baby, in a procedure performed with violations, or in low-quality tuberculin. In any case, the doctor will prescribe a number of diagnostic procedures. Sometimes the result depends on the individual characteristics of the child’s body, so the sample is evaluated over time, comparing with last year’s results.

Why is Mantu checked after 72 hours?

If you check the reaction of the child’s body earlier, the papule has not fully formed. In the first hours, the injection site resembles a mosquito bite, and there is redness around it. It is on the 4th day that the swelling subsides, and the papule acquires reliable features.

And 5 days after the tuberculin injection, the papule decreases in size, which will also distort the results. Therefore, it is necessary and possible to check mantu on day 4 - 72 hours after administration of the drug. But on the 5th day, the reaction to the administration of the drug can no longer be checked.

Most often, kindergarteners and schoolchildren are given a tuberculin test on Friday so that the reaction can be checked on Monday. If mantu was made on Monday, when to check? Doctors schedule an examination for Thursday, around the same time. If the sample was taken on Tuesday, it is checked on Friday.

Who checks Mantu at the clinic? As a rule, this is the same nurse who administered the “vaccination”. It could also be a pediatrician or phthisiatrician - a doctor involved in identifying, treating and preventing tuberculosis.

When sending your child for a tuberculin test, calculate how many days doctors check Mantoux. If it is not possible to show the child to a specialist on this day, it is better to reschedule the test to a more convenient time. It is better to temporarily postpone the “vaccination” than to torment yourself with anxious doubts and your child with the need for a repeat procedure.

Is it possible to wet the injection site?

Some doctors argue that Mantoux should not be wetted, as this will lead to a false positive result. However, such a ban is unfounded. The Mantoux test involves intradermal injection of tuberculin, so contact of water with the drug is possible only if the liquid gets inside the skin. This will require an injection. Only in this case an allergic reaction is possible.

But why do doctors universally prohibit getting the injection site wet? This is due to the history of tuberculosis diagnostic methods. In the early seventies, the body's reaction to Mycobacterium Bovis was monitored using skin tests: the Pirquet or Koch test. These methods consisted of placing a solution of a diagnostic drug on the skin, where fine incisions were subsequently made. The results of such a test could indeed change if a person had contact with water, which can wash the allergen from scratches.

What happens if you wet the sample?

So, is it possible to wet Mantu? Brief contact of the tuberculin injection site with water is not capable of distorting the examination results. Therefore, the child can be bathed any day after the test is performed. However, it is better to limit contact between the injection site and water, which is likely to provoke an allergic reaction.

Why can't you wet Mantu? In rare cases, after water procedures, the papule can sharply increase in size. You must immediately notify your doctor about this. In this case, the tuberculin test will be uninformative, and the examination will have to be repeated.

How long can you not soak Mantu? Doctors say that you should not come into contact with the liquid immediately after injecting the drug. After all, water can penetrate the skin through an unhealed puncture. Therefore, it is recommended to exclude any contact with moisture within an hour after visiting the treatment room. This time is enough for the injection site to become clogged with clotted blood.

How to check the Mantoux reaction yourself in a child

If we found out how many hours later Mantoux is checked, is it possible to carry out the inspection yourself? Of course, you can see what size the “button” has become and compare the indicators with the norm on your own, before coming to the doctor. But only a doctor will give an adequate conclusion.

How to test Manta in a child’s home yourself:

• Note the size of the redness, but do not take it into account when measuring
• Pay attention to whether there is a seal inside and its size
• If desired, use a pen to circle the papule itself without touching the redness - this will make it easier to determine the size of the “button”
• Use a clear plastic ruler to measure the size of the seal.
• Take care in advance of high-quality natural or artificial lighting - the papule is tiny, a few millimeters in size

If on the 4th day, in good light, the Mantoux reaction is almost invisible, the test is considered negative, and the child does not have tuberculosis

Mantoux reaction dimensions:

• From 0 to 1 mm – negative reaction
• 2-4 mm – the reaction is considered doubtful, the child is included in the risk group
• A papule larger than 5 mm indicates that the child is highly likely to be sick. The diagnosis is not made based on the reaction to the tuberculin test alone. Conducts additional research
• Over 17 mm – the so-called hyperergic reaction, which is a serious symptom of tuberculosis

In children who have not been vaccinated with BCG or are older than 6 years, there should be no papule, or its size should be no more than 1 mm. Then the sample is considered negative. Previous vaccinations, allergic reactions, infection with parasites, colds and infectious diseases, blood transfusions, incorrectly performed procedures, and violations of the rules for caring for the injection area can lead to unreliable results. Mantoux vaccination can only be given a month after the previous vaccination or previous illness.

The size of the papule depends on the age of the child. The doctor also examines how much the current Mantoux reaction is greater than the previous one. If this difference is 6 mm or more, there is cause for concern.

If your child experiences itching in the injection area after the injection, do not allow him or her to scratch the area. An infection may get into the wound, and the test results will be unreliable. For the first few days, you should not smear Mantu with iodine, brilliant green, antipruritics, or wet it. This can also affect the result. For several days after the tuberculin test, it is advisable not to give the child allergens - chocolate, oranges, etc.

As we said, the Mantoux reaction is checked after 3 days, but in some cases the child must be shown to the doctor before the appointed time.

The child should be seen by a doctor immediately if the following symptoms appear:

• Significant increase in body temperature
• Weakness, dizziness and general poor health
• If severe inflammation or even pus appears in the injection area

Such a reaction may indicate an allergy to tuberculin. However, these phenomena are rare.

If the test shows a positive result, the doctor prescribes a set of other diagnostic procedures. They examine sputum, do chest x-ray, and examine other family members. If necessary, anti-tuberculosis therapy is prescribed.

results

Mantoux is assessed no earlier than 2-3 days after the injection. Using a ruler with a millimeter scale, the transverse diameter of the infiltrate is measured in relation to the axis of the forearm.

The category of vesicular-necrotic reactions includes pronounced manifestations in the form of large papules with the formation of areas of necrosis in the central part and pustules under the skin. Often the whole process is accompanied by lymphangitis.

The Mantoux reaction is considered to be increasing in cases where there is a dynamic increase in the diameter of the infiltrate by 5 mm or more when compared with the size of previous reactions.

Often in children you can get a false negative result (negative Mantoux with a confirmed infection), which occurs when:

• a weak immune system that is unable to adequately respond to a tuberculin injection (typical for any immunodeficiency);
• recent infection (up to 2 months);
• up to 6 months of age.

The result may be false positive (large papule in the absence of tuberculosis infection in the body) in cases where:

• the body is infected with other (non-tuberculous) mycobacteria;
• allergic reactions are present;
• the child has recently suffered from other diseases of bacterial etiology;

Dr. Komarovsky especially strictly calls for monitoring the sequence of events - BCG vaccination and Mantoux.