Mantoux reaction, Diaskin test, quantiferon test, T-spot, PCR, or maybe fluorography? Let's tell you more.
Tuberculosis in Russia is so widespread that by the age of forty, 70-90% of the inhabitants of our country are infected with it. This does not mean that they are sick: after infection, the immunity of most people cope with the bacteria. The probability of getting sick is on average 8% in the first two years after infection, then gradually decreases, and acquired cellular immunity is formed. Among adults, people who are weakened, living in poor conditions, with a lack of light and fresh air are more likely to get sick. Nevertheless, absolutely every one of us can get infected. Therefore, it is so important to have regular tuberculosis tests and check your children.
Why is the BCG vaccine needed?
WHO recommends mass vaccination of newborns against tuberculosis in all countries where the disease is common. Therefore, 3-5 days after birth, while still in the hospital, all newborns are vaccinated with BCG free of charge. But this vaccine does not protect against tuberculosis infection. Its task is somewhat different. If an unvaccinated child under 2 years of age becomes infected with tuberculosis, he is extremely likely to develop tuberculous meningitis and generalized forms of tuberculosis, which very quickly lead to death. BCG reliably enough protects the child from these forms. It also protects children from pulmonary tuberculosis, but less effectively.
What other vaccinations do children under 2 need?
Mantoux test
The Mantoux test is performed annually for all children under 7 years of age. This is not a vaccination (!), But an immunological test showing whether there is a tuberculosis pathogen in the body. At the same time, tuberculin, specific protein-containing antigens of human and bovine tuberculosis, is injected intradermally. After 72 hours, the size of the papule is measured. The result of the Mantoux reaction can be influenced by going to the sauna, taking a long bath, swimming pool, and brushing the injection site. Temporary contact with water does not in any way affect the results of the Mantoux test, therefore the opinion that Mantoux should not be wetted is a myth.
Diaskintest test
It is held for children from 8 years old. It is also a skin test. But if in Mantoux antigens of both human and bovine tuberculosis are used, then in diaskintest only antigens of human tuberculosis are used. Diaskintest is much more specific: a reaction to it occurs only if there are active tuberculosis bacteria in the body. Simply put - if the Mantoux test is positive, this still does not mean anything: this test often gives false-positive reactions. But after the diaskintest, a reaction appeared - this is a more serious indicator.
Mantoux accuracy is 50-70%, diaskintest - 90%.
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Quantiferon test
The quantiferon test is one of the new methods for diagnosing tuberculosis by blood tests. It is based on the determination of gamma-interferon in the blood, which is produced by cells in response to the introduction of a tubercle bacillus. Unlike Mantoux and Diaskintest, the quantiferon test does not require the introduction of any antigens and bacteria into the body. Blood for research is taken from a vein. The result is ready in a few days and is much more accurate than skin tests. The test will only be positive if the person is really sick.
T.SPOT.TB (tee-spot)
This method of diagnosing tuberculosis by blood is similar to the quantiferon test. The difference is that the quantifieron test detects interferon-gamma in the blood, produced in response to the introduction of a tubercle bacillus, and the T-SPOT detects the T cells themselves, which produce interferon-gamma for the presence of mycobacterium tuberculosis. Both tests are equally sensitive and informative (up to 97%), they are more sensitive than Diaskintest and much more sensitive than the Mantoux reaction. "T-spot" practically excludes false positive and false negative reactions, while the quantiferon test can still give a false positive reaction if, for example, a person was sick with ARVI during the donation of blood.
Comparative characteristics of four tests for tuberculosis
| Mantu | Diaskintest | The quantiferon test | T.SPOT. TB | |
| accuracy | 50,00% | 90,00% | 97,00% | 97,00% |
| Evaluation of data | Subjective | Subjective | Objective | Objective |
| False-positive results | often | rarely | Extremely rare | No |
| With a latent form of tuberculosis | Not sure | Not sure | Reliable | Reliable |
| contraindications | A lot | eat | No | No |
| Adverse reactions | eat | rarely | No | No |
| In HIV and other immunodeficiencies | Not informative | Not informative | Informative | Informative |
| How to research | Skin test | Skin test | Blood test | Blood test |
PCR
To distinguish the active form of tuberculosis from latent, a specific test is used - PCR (research of sputum on DNA). Thus, diaskintest, tee-spot, and other tests allow to determine whether a person is ill with tuberculosis at all (pulmonary or extrapulsion), and PCR - whether he is ill with them in an active form.
fluorography
All adults from the age of 15 in Russia are recommended to undergo fluorography once a year. Children from 15 to 17 years of age are allowed to perform Fluurography, but this does not cancel the staging of Diaskintest. A certificate with a fresh picture is required everywhere - even when visiting a child in the hospital. Fluorography is more of a "collective barrier" to TB than a method of choice for individual testing. Fluurography detects only pulmonary forms of tuberculosis.
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