Interferon-γ release assays: New diagnostic tests for Mycobacterium tuberculosis infection, and their use in children

Purpose of Review: The testing and treatment of children at risk for Mycobacterium tuberculosis infection represents an important public health priority in the United States. Until recently, diagnosis has relied upon the tuberculin skin test (TST). New interferon-γ release assays (IGRAs) offer improvements over TST, but these tests have not been studied in children until recently. RecentFindings: Evidence regarding IGRA performance in children is accumulating rapidly. Overall, the findings demonstrate performance of IGRAs equivalent or superior to that of the TST. However, IGRAs have biological limitations similar to TST and some technical problems of their own, and critical gaps in our knowledge remain. Summary: Current evidence supports usage of IGRAs in children aged 5 years or older. IGRAs are preferred over TST when specificity is paramount or wherein patients might fail to return for TST reading. Evidence for use in children aged less than 5 years is insufficient at this time: the sensitivity is poorly defined, and TST is preferred for testing these children. Future IGRA research should focus on children aged less than 5 years for informing expanded usage in this vulnerable population.