What is the best test for tuberculosis?
What are
There is a Mantoux test, Diaskintest (a test with recombinant tuberculosis allergen), a quantiferon test (gamma-interferon test), a T-SPOT TB test. These tests are prescribed by a doctor in accordance with the instructions for use and order 109 “On the improvement of anti-tuberculosis measures in the Russian Federation.”
The Mantoux test is a test to determine anti-tuberculosis immunity after vaccination against tuberculosis (BCG) and after meeting with a patient with tuberculosis, as well as to determine the presence of the disease. Distinctive from other tests, the indication of the sample: the selection of children for re-vaccination against tuberculosis at 7 years. The test is recommended for children after BCG vaccination from 1 year to 7 years inclusive annually.
In the absence of vaccination against tuberculosis and in a number of chronic diseases, it is recommended every six months, starting from the age of 6 months. During the test, killed particles of bacteria that do not cause tuberculosis are injected intradermally. The result is evaluated by a doctor, paramedic or specially trained nurse 72 hours after the test.
“In Russia, children undergo a Mantoux test once a year. But for some categories of children – 2 times a year, – says pediatrician, neonatologist, infectious disease specialist at GMS Clinic Emilia Gavrilova . – These are children and adolescents: with HIV infection, diabetes mellitus, chronic non-specific diseases of the respiratory system, gastrointestinal tract, from among migrants, refugees, internally displaced persons, unvaccinated against tuberculosis, receiving corticosteroid, radiation, cytostatic and immunosuppressive therapy, living in social service organizations that are under dispensary observation in narcological and psychiatric specialized medical organizations.
Diaskintest to determine the presence or absence of tuberculosis in children and adults. It is indicated for children from 8 to 17 years old inclusive, as well as for adults to exclude tuberculosis. The test is prescribed for children and up to 8 years of age if there are indications determined by a doctor to exclude active tuberculosis.
Technically, the test is carried out in the same way as the Mantoux test, but a special protein is injected intradermally, which only reacts to active tuberculosis in the body. Therefore, there are fewer reactions to Diaskintest in the form of redness and swelling on the skin. The result is evaluated by a doctor, paramedic or specially trained nurse 72 hours after the test.
The quantiferon test (interferon gamma test) and the T-SPOT TB test are used as alternative diagnostic methods for detecting TB when skin testing is contraindicated. Both tests are carried out in a test tube, however, for the tests, blood is taken from the vein of the subject. These tests are allowed during pregnancy, unlike intradermal tests.
T-SPOT TV is an informative test in determining tuberculosis in HIV-infected people, people with oncological and autoimmune diseases, while intradermal tests sometimes show negative results. The result is evaluated by a phthisiatrician. Each of the listed methods for diagnosing tuberculosis becomes informative two months after contact with a patient with tuberculosis. Therefore, there is no point in doing these tests earlier.
The Mantoux test and Diaskintest are not recommended for acute and exacerbation of chronic diseases, for allergic reactions, epilepsy, in the presence of quarantine in children’s groups, immediately after vaccination. After the quarantine is lifted and one month after the disappearance of the clinical symptoms of an acute or chronic disease, as well as one month after vaccination, testing is allowed.
The quantiferon test (interferon gamma test) and the T-SPOT TB test have no contraindications, as they are carried out inside a test tube with the blood that is taken from a vein.
