Diagnostic utility of QuantiFERON-TB Gold In-Tube test in pediatric tuberculosis disease in Taiwanese children

PurposeTo compare the performance of a commercial interferon-gamma release assay, QuantiFERON TB Gold-in-Tube (QFG-IT) with the tuberculin skin test (TST) in Taiwanese children for the diagnosis of active tuberculosis (TB).MethodsA retrospective chart analysis of pediatric patients (<18 years of age) who underwent QFG-IT tests and TST for the confirmation of active TB between January 2008 and June 2014.ResultsThe sensitivity of QFG-IT was 100% [95% confidence interval (CI): 63.1-100], versus sensitivity of 62.5% for TST (95% CI 24.5-91.5). The positive predictive value of QFG-IT was 100 (95% CI: 89.7-100), while the negative predictive value for TST was 86.9% (95% CI: 67-96.3). Among three patients with Bacillus Calmette-Guérin (BCG) osteitis, two patients with TST were positive, but all tested samples for QFG-IT were negative.ConclusionQFG-IT assay was more sensitive for the diagnosis of TB disease than TST in an intermediate burden population with universal neonatal BCG vaccination. The increased recognition of BCG induced osteitis in recent years has alerted physicians that BCG induced lesions should be suspected when TST is positive but QFG-IT is negative. Despite higher costs for QFG-IT than TST, they have additional value for the diagnosis of active TB and should be performed when a diagnosis of TB remains in doubt.