Should I worry if Mantoux is negative?

Indications for Tuberculin vaccination

Tuberculin is used for tuberculin diagnostics (carrying out an intradermal Mantoux tuberculin test), which is an indicative diagnostic test for the purpose of:

• identifying the need for a patient to be vaccinated against tuberculosis with BCG
• diagnosis of tuberculosis;
• determining whether the population is infected with Mycobacterium tuberculosis (or the state of hypersensitivity to tuberculin, if the existing post-vaccination allergy does not give grounds to talk about infection).

The active substance of the drug (allergen-tuberculoprotein) causes, when performing an intradermal tuberculin test in people infected or vaccinated with BCG/BCG-M, a specific delayed-type hypersensitivity reaction in the form of a local reaction - hyperemia (redness) and infiltrate (papule formation).

Why is there a negative Mantoux after BCG?

Negative Mantoux after BCG can be considered normal and cause the need for examination, it depends on the initial data:

• If the child is from 3 years old to 6-7, the reaction should be like this. Here, the absence of a papule means that the body is protected by the vaccine, but it was administered quite a long time ago. It is also considered after 13-14 years of age in children who were revaccinated at the age of 7.
• If a child is 1-2 years old or 7-12 years old, in the older group, repeated BCG was performed, the reaction indicates that the vaccination did not give the desired effect. And the body is poorly protected from Koch’s bacillus.

Repeated BCG
It is impossible to discount the factors that distort the result, and the fact that BCG vaccination is not always done on schedule due to illness.

Virus of tuberculin test

Doctors also have the concept of “tuberculin test turn”, that is, immediately after administration of the drug there was an absence of papule and redness, and after a few hours or days a positive reaction occurred. Most often this happens due to the following factors:

• moisture getting into the injection site;
• penetration of infection through the wound;
• scratching or otherwise traumatizing the puncture;
• allergy to tuberculin (the rarest cause);
• the child has diabetes or asthma;
• Koch's bacillus still settled in the body.

The latter is also rare, and in most cases this reaction is false positive, and the child does not have tuberculosis.

Evaluation of Mantoux test results

The test result is assessed by a doctor or trained nurse 72 hours after the test. A reaction to tuberculin is possible in the form of hyperemia (redness of the skin) and the formation of a papule (a dense round area rising above the skin). Assessment of the Mantoux test consists of taking into account the size of the papule and assessing the severity of hyperemia. The measurement is carried out in a direction transverse to the axis of the hand, the result is taken into account in millimeters. Only the size of the papule is measured, and not the size of the area of ​​hyperemia (redness). The size of the redness is taken into account only when the papule has not occurred.

Reaction options for the Mantoux test:

• negative - there are no changes on the skin;
• doubtful - there is redness of any size without a papule, or a papule no more than 2-4 mm;
• positive mild - papule size 5-9 mm;
• positive of medium intensity - papule size 10-14 mm;
• positive pronounced - papule size 15-16 mm;
• excessive (hyperergic) - the size of the papule exceeds 17 mm or there are pronounced signs of inflammation (reaction of the lymph nodes, skin ulceration, etc.).
• A negative Mantoux reaction indicates that the body does not have antibodies that are “familiar” with the tuberculosis bacterium. This means that the child is not infected, or there is no immune reaction to BCG vaccination.
• A questionable sample is considered negative.
• A positive test can be either a consequence of BCG vaccination or a sign of infection.

To assess the likelihood of infection, you need to look at the turn of the tuberculin test - the transition of a negative Mantoux reaction to a positive one (not associated with previous vaccination) or an increase in the diameter of the papule compared to the result of the previous test by 6 millimeters or more.

Also signs of infection are:

• hyperergic reaction;
• persistent (more than 4 years) persistent reaction with a papule of 12 mm or more;
• gradual (over several years) increase in sensitivity to tuberculin with the formation of an infiltrate measuring 12 mm or more.

A positive Mantoux test result without taking into account other diagnostic criteria is not a basis for making a diagnosis or starting any treatment.

Only a doctor can evaluate the reaction; if necessary, the child will be referred for additional examination to a TB specialist.

Mantoux reaction is negative - what does it mean?

If a negative Mantoux reaction is detected, this means that:

• There is no Koch bacillus in the body. This happens when the BCG vaccination was done quite a long time ago, or the child was not vaccinated against infection at all. But in both cases it's good. For vaccinated children, a test result with a minus sign is the norm from 3 to 6-7 years after vaccination, as well as at 13-14 years after revaccination.
• The BCG vaccination did not give the desired effect, that is, the child did not develop immunity against tuberculosis. This is not very good for children 1-2 years old, as well as 8-12 year olds who were given BCG in the maternity hospital and revaccinated at 7 years old. For unvaccinated people, the lack of immunity against tuberculosis is the norm, which simultaneously indicates a lack of contact with the Koch bacillus.

Indications for the Mantoux test

The Mantoux test is performed to diagnose tuberculosis.

Children vaccinated against tuberculosis:

The Mantoux test (Intradermal allergy test with tuberculin) is performed once a year, regardless of the results of previous tests, at the age of 1 to 7 years inclusive.

For children not vaccinated against tuberculosis (children who have not been vaccinated with BCG), the Mantoux test is performed 2 times a year starting at the age of 6 months

Children not vaccinated against tuberculosis:

The Mantoux test is performed - 2 times a year, starting from the age of 6 months, the Mantoux test is performed.

What does a negative Mantoux test look like?

A negative Mantoux test appears externally as:

• absence of redness at the injection site;
• absence of tubercle (papules);
• the presence of a small seal up to 1 mm in size and a red dot on it.

It is checked 72 hours after the manipulation. To ensure the reliability of the result, it is important not to wet the puncture site, not to rub it, not to bandage it, not to smear it with anything or seal it with anything.

Negative Mantoux reaction

Contraindications

Only a doctor can decide whether the drug “Tuberculin” is suitable for testing for tuberculosis.

“Tuberculin” is contraindicated for persons with allergic and autoimmune diseases!

The use of Tuberculin is also contraindicated in the following cases:

• common skin diseases
• epilepsy
• acute, chronic infectious and somatic diseases during exacerbation; allergic conditions (rheumatism in acute and subacute phases, bronchial asthma, idiosyncrasies with pronounced skin manifestations during exacerbation).

It is not allowed to carry out the Mantoux test in those children's groups where there is a quarantine for childhood infections. The Mantoux test is performed 1 month after all clinical symptoms disappear or immediately after quarantine is lifted.

What to do if the Mantoux test is bad

A bad Mantoux test, when it is a negative reaction to tuberculin, dictates the need for additional examination. The young patient is referred to an appointment with a phthisiatrician. The specialist examines the patient, interviews the parents, and studies the results of their recent fluorography. And the child is prescribed Diaskintest - a more informative test for tuberculosis. It will more accurately identify or force the diagnosis to be excluded.

If the Diaskintest is positive, an X-ray of the lungs is also taken, and infection-killing drugs are prescribed.

It is necessary to find or eliminate reasons that can distort Mantoux. After all, these may be other diseases that have not yet been identified, not just tuberculosis. They are being looked for after Diaskintest confirmed the absence of Koch's bacillus in the body.

Possible side effects

• For most, the test process is asymptomatic.
• Headaches may rarely occur
• General weakness, sleep disturbances, and increased body temperature rarely develop.
• Individuals with altered reactivity experience allergic reactions.
• Considering the possibility of developing immediate allergic reactions (anaphylactic shock, Quincke's edema, urticaria) in particularly sensitive individuals, vaccinated persons must be provided with medical supervision for 30 minutes.

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When a phthisiatrician is needed with a negative tuberculin diagnosis

They are referred to a specialist if a test with a minus sign is noted one year after BCG. All the more necessary is a phthisiatrician when the same thing repeats from year to year. This does not mean that the child has an infection. But his risk of getting sick is higher than other children. Therefore, after each questionable sample with a minus sign, additional examination is required.

We recommend reading the article about the causes of Mantoux allergy. From it you will learn about what provokes the development of allergies to the Mantoux vaccine, who is more susceptible to allergies among children, what to do if symptoms appear in a child. And here is more information about when Suprastin is needed before Mantoux.

It is quite difficult for a non-specialist to understand whether a negative Mantoux reaction is normal or not; there are too many influencing factors. Therefore, you should entrust the assessment to a doctor when 3 days have passed after the test. And parents need to remain calm and make sure that nothing violates its authenticity. Then you should follow the doctor’s recommendations if a negative Mantoux indicates a problem.

Mantoux...explain, I'm confused...

My son was given mantu at both one and two years old, nothing appeared at the injection site, i.e. the reaction is negative. The doctor looked at me on the third day and said everything was fine!

Our furnace friends, on the contrary, developed a small inflammation, like a mosquito bite. The doctor also told them that everything was fine.

And this friend claims that not everything is so good with us, according to her, if nothing appeared after Mantu, this means that after BCG (done in the Maternity Hospital) the child did not develop immunity to tuberculosis and we will have to do it again BCG.

I read a lot of information on this topic on the Internet.

The Mantoux test is the body’s reaction to the introduction of tuberculin.
At the site of injection of the drug into the skin, specific inflammation occurs, caused by infiltration by lymphocytes - specific blood cells responsible for cellular immunity. If the body has already had a chance to “get acquainted” with the real Mycobacterium tuberculosis, then there will be more such lymphocytes, the inflammation will be more intense, and the reaction will be “positive”. By measuring the diameter of a papule (inflammatory “plaque” or “button”) with a ruler, you can assess the strength of immunity to the tuberculosis bacillus. Tuberculin does not carry the tuberculosis bacillus, as the name might suggest.
It contains only the products of its vital activity. Vaccination To prevent tuberculosis, BCG vaccination is given to newborns aged 3–7 days. Repeated BCG vaccination is given to children aged 7 years. In 90% of children, a scar forms at the site where the BCG vaccination was given. A year after BCG, the scar is measured and its character is recorded. In the absence of a scar, a repeat BCG vaccine is given only if the Mantoux test is negative and not earlier than 2 years after the primary vaccination and a year after revaccination.

Classification of Mantoux test results

The reaction is considered:

• negative
  or in the complete absence of infiltration (compaction) or in the presence of a prick reaction (0-1 mm);
• doubtful
  - with an infiltrate (papule) measuring 2-4 mm with only hyperemia (redness) of any size without infiltration (compaction);
• positive
  - in the presence of a pronounced infiltrate (papule) with a diameter of 5 mm or more. Reactions with an infiltrate size of 5-9 mm in diameter are considered weakly positive; medium intensity - 10-14 mm; pronounced - 15-16 mm;
• hyperergic
  (i.e. too pronounced) in children and adolescents is considered a reaction with an infiltrate diameter of 17 mm or more, in adults - 21 mm or more, as well as a vesiculo-necrotic (i.e. with the formation of pustules and necrosis) reaction, regardless of the size of the infiltrate, lymphangitis, daughter dropouts, regional lymphadenitis (enlarged lymph nodes).

And now I found what a negative reaction means:

1. A negative reaction means that the child’s immunity to tuberculosis has not yet formed, therefore, the risk of the disease remains.

2. If after mantoux the result is negative (no papule). Or the injection site. This means that the child is not tubular infected, or if the papule was 4 mm before, but now it is 2 mm (for example), this means a negative reaction! But if the papule increases, then the reaction is positive.

3. The vaccine has already stopped working.

4. A negative reaction means a good result.

And what is the truth???