QuantiFERON®-TB Gold In-Tube assay vs. tuberculin skin test in Indonesian children living with a tuberculosis case

SETTING AND OBJECTIVES: The tuberculin skin test (TST) has limitations in diagnosing latent tuberculosis (TB) infection (LTBI). Interferon-gamma release assays may improve diagnostic accuracy. We compared Quanti-FERON (R)-TB Gold In-Tube (QFT-GIT) and TST in Indonesian children. DESIGN: Children aged from 6 months to 9 years exposed to a TB case at household and neighbourhood levels were recruited. The children underwent QFT-GIT and TST. Test responsiveness was assessed according to an exposure gradient. RESULTS: A total of 299 household-exposed and 72 neighbourhood-exposed children were analysed. Overall, respectively 46% and 41% were positive using QFT-GIT and the TST. Test positivity increased with exposure (QFT-GIT P value for trend <0.001, and TST P < 0.001); however, only QFT-GIT responded significantly to a 'within-household' gradient. The TST was less likely to be positive than the QFT-GIT in neighbourhood-exposed children (P = 0.05). BCG-vaccinated children were less likely to be QFT-GIT-positive, while older children were more likely to be QFT-GIT-positive. Both tests had increasing positivity with increasing smear grade. CONCLUSION: QFT-GIT performed similarly to the TST in Indonesian children living with an infectious TB case. Test accuracy was not compromised by young age or BCG vaccination. Our findings suggest that QFT-GIT offers little advantage over the TST in this population. High rates of LTBI diagnosed in household-exposed children by both tests support preventive therapy.