To evaluate the efficacy and diagnostic potential of interferon- gamma release assays QuantiFERON-TB Gold® In Tube (QFT-TB-IT) for the detection of gamma interferon against the antigen ESAT-6, CFP-10, TB 7.7(p4) of Mycobacterium tuberculosis and compare the reactivity with other methods (smear, culture and IS6110 targeting PCR). The study was carried out on children with pulmonary and extra pulmonary tuberculosis along with matching and PPD+ controls (82 cases, 48 matching controls and 20 PPD+ controls). QFT-TB-IT showed a significantly higher sensitivity (51.2%) as compared with LJ medium culture method (11.0%; p < 0.001), BacT/Alert 3D system (12.1%; p < 0.001), ZN staining (19.5%; p < 0.001) and PCR (45.1%; p < 0.05). Specificity of QFT-TB-IT was 48.0%. Less specificity of this assay may be due to high endemicity of tuberculosis. However, further studies are recommended.