Diagnostic value of interferon- gamma release assays (QuantiFERON-TB Gold® In Tube) in childhood tuberculosis.

Objective: 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).

Methods: 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).

Results: 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%.

Conclusions: Less specificity of this assay may be due to high endemicity of tuberculosis. However, further studies are recommended.