IGRA shows 87% sensitivity, 98% specificity for TB infection in children under 5 in low-prevalence settingsHow well does a blood test spot TB in young children?

<sec><title>BACKGROUND</title>Interferon-gamma release assays (IGRAs) have largely replaced the tuberculin skin test (TST) for diagnosing TB infection (TBI) in low-TB-burden countries, except in young children. This review assesses the diagnostic accuracy of IGRAs in children under 5 years old, using TST as a reference, for detecting TBI.</sec><sec><title>METHODS</title>A systematic review was conducted in MEDLINE, Embase, Web of Science, Scopus, and LILACS to identify studies published up to November 2024 that performed simultaneous IGRA and TST for TBI in children under five in low-TB-prevalence settings. Studies in mid- or high-burden countries involving immunocompromised children, TB disease, or non-TB mycobacteria, as well as studies lacking paired IGRA and TST, were excluded. A meta-analysis quantified the sensitivity and specificity of IGRA and explored heterogeneity.</sec><sec><title>RESULTS</title>Thirty-one reports met the inclusion criteria, providing 5,679 paired results. Compared to the TST, pooled sensitivity for IGRAs was 87.3% (95% confidence interval: 73.0-94.1), while specificity reached 98.3% (95% confidence interval: 95.7-99.2).</sec><sec><title>CONCLUSION</title>These findings support the use of IGRA for diagnosing TBI in young children in low-prevalence settings. We recommend a cautious approach in high-risk children, including the combination of both tests.</sec>.