Role of Quantiferon TB gold test in diagnosis of latent tuberculosis infection(LTBI) in childhood and its correlation with tuberculin skin test

Abstract

Tuberculosis is a significant health problem among children population worldwide. Timely diagnosis and treatment of the disease are the basis for prevention of its further spreading. However, the diagnosis of latent tuberculosis infection is a challenge because there is no gold standard. The aim of this study was to evaluate the importance of the diagnostic Quantiferon TB gold test in the diagnosis of latent TB infection and to correlate it with Tuberculin skin test according to the Mantoux method. For the realization of this study we analyzed 32 patients examined for possible M. tuberculosis infection at the Institute of Respiratory Diseases in Children, Kozle, Skopje. The study included 16 girls and 16 boys, aged 9 months to 17 years, with an average age of 6.96 ± 4.49 years. In all children basic biochemical analyses were made: аcid-alcohol-resistant bacilli in a direct sample of sputum, Levenstein Jensen cultures, chest X-ray, tuberculin skin test according to the Mantoux method and Quantiferon TB gold test. The results showed that 24 patients had a BCG scar. All participants in this study had normal radiographic findings of the lungs. In 4 cases Quantiferon TB gold test was positive, while in 28 patients the test was negative. Tuberculin skin test was positive in 13 subjects. In children with negative Quantiferon TB gold test LTBI was excluded and drug prevention with Isoniazid was not started or it was interrupted. Determination of IFN-γ contributes to better diagnosis of LTBI and in reducing the unnecessary drug use. Using Quantiferon TB gold test may be an alternative tool for Tuberculin skin test in the diagnosis of tuberculosis in countries where vaccination with BCG is widespread.