Latent Tuberculosis Infection - Diagnosis and Treatment

Latent tuberculosis infection (LTBI) is defined as a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens without evidence of clinically manifested active tuberculosis (TB). Diagnosis and treatment for LTBI are important for TB, especially in high-risk populations. Tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) are used to diagnose LTBI.

The study aims to present the first results with IGRA test compared with TST in the screening of LTBI and the treatment results in the cases with LTBI in Macedonia.

In this study 73 cases diagnosed and treated with LTBI in 2016 were included. For diagnosis of LTBI, we used TST RT -23 5T.U. and commercial IGRA test such as QuantiFERON-TB Gold In-Tube (QFT-IT).

Out of 73 cases with LTBI, 61.64% were men, and 38.36% were women. Among all age groups, the most frequent were cases between 5 and 14 years old (54.79%). Among the evaluated risk groups for LTBI, the most frequent were children household contacts with pulmonary TB cases (61-83.65%), followed by people living with HIV (9-12.33%) and only 3 cases with other medical reasons. Positive TST had 34 cases (46.57%) and positive IGRA test 25 cases (34.25%). Regarding the treatment regimes, we use two regimes: 50 cases (68.44%) received 6 months daily regime with Isoniazid, and 23 cases (31.51%) received 3 months daily regime with Isoniazid and Rifampicin. Treatment outcomes showed that the most patients completed treatment regimes: 55 (75.34%) and only 10 (13.09%) interrupted the treatment.

Despite the progress made in the last few years, several challenges remain to be addressed for better management of LTBI which will contribute to strength TB control in the country.