Use of Interferon-Gamma Release Assays in Children <2 Years Old

While interferon-gamma release assays (IGRAs) are widely used for detecting tuberculosis (TB) infection, tuberculin skin tests (TSTs) remain preferred for children under the age of 2 years. The preference for TST stems from concern over IGRA sensitivity in young children. However, TSTs are susceptible to false-positive results following Bacille Calmette-Guérin (BCG) vaccination, which is common in infancy, and exposure to nontuberculous mycobacteria. We reviewed available data for IGRA performance in children under age 2 years. Across four cohorts of high-risk children under age 2 (mostly case contacts or those born in tuberculosis endemic regions), 0 of 575 untreated children with negative IGRA test results progressed to tuberculosis disease-including 0 of 70 who were TST positive but IGRA negative. While neither TSTs nor IGRAs are perfectly sensitive for the diagnosis of tuberculosis infection, IGRAs are an acceptable alternative to TST in children <2 years of age.