Evaluation of Interferon-gamma Release Assay in Children with Confirmed Tuberculosis

Purpose: This study aimed to evaluate the diagnostic value of the QuantiFERON-TB Gold In-Tube (QFT-GIT) in children with confirmed tuberculosis (TB). Methods: We retrospectively reviewed the medical records of children aged 18 years who underwent both QFT-GIT and Mycobacterium tuberculosis culture between 2006 and 2017. Confirmed TB was defined as the presence of at least one positive specimen for M. tuberculosis on culture or a nucleic acid amplification test. Results: Of the 582 patients included in the analysis, 48 were confirmed to have TB. The sensitivity and specificity of QFT-GIT for the diagnosis of confirmed TB were 85.4% and 95.5%, respectively. Among children with confirmed TB, the proportion in the immunocompromised state was higher in the QFT-GIT negative group than in the QFT-GIT positive group (50.0% vs. 5.7%, P=0.010). The median age at sampling was lower in the QFT-GIT indeterminate group than in the QFT-GIT positive group (7 years vs. 17 years, P=0.008), and the proportion of immunosuppression was higher in the QFT-GIT indeterminate group than in the QFT-GIT positive group (42.9% vs. 5.7%, P=0.017). The interferon gamma response to mitogen control was significantly higher in the 10-18 years group than in the 0-9 years group (P<0.001), and was significantly higher in the immunocompetent group than in the immunocompromised group (P=0.001).