Latent tuberculosis infection in interdisciplinary aspects of diagnosis of tuberculosis (phthisiologist’s review and comments)

Massive proportion of world’s population (nearly 1/3 of mankind, according to the WHO estimates) have latent tuberculosis infection (LTBI). Persons with LTBI are not ill and not infectious to those around them, but the lifetime risk of developing active TB is 5–20% among infected persons, with the majority developing TB disease within 2–5 years after infection. LTBI is a reservoir for future TB cases, and without control over it, all efforts to fight against TB will be brought down to a minimum. This issue is the most pressing one in the pediatric practice, as the main mass methods for detecting LTBI now are immunological TB tests, which are used in children’s primary care facilities on a mass scale. The objective of this review is determined by the necessity to improve knowledge regarding latent tuberculosis infection in children and adolescents as a predictor of the local tuberculosis for the timely formation of groups at high risk of exposure to TB disease and arrangement of preventive measures. 27 articles have been selected for screening during the search process according to the key words after removal of dublicates in the databases. The paper presents new guiding documents, phthisiologist’s comments taking into account interdisciplinary interaction on the issues of screening and monitoring of TB to identify individuals with LTBI. The importance of skin tests as screening methods remains indisputable, given a certain preference for high sensitivity of test results over their specificity. Mantoux skin tests using 2 tuberculin units (TU) of purified protein derivative (PPD)-L and a test with recombinant tuberculosis allergen (RTA) due to their high sensitivity, simplicity and cost effectiveness are the most preferred diagnostic tools for detecting LTBI, which are perfectly suited for mass screening of population. Laboratory diagnostic tests assessing release of interferon gamma in vitro by T-lymphocytes (IGRA-tests) are presented. The results of these tests can be considered when conducting routine tuberculosis screening.