Toward tuberculosis elimination strategy: the role of IGRA on immunocompetent individuals

Tuberculosis infection (TBI) affects approximately one quarter of the global population and constitutes the principal reservoir sustaining future cases of tuberculosis disease (TBD). Interferon-gamma release assays (IGRAs) have become central tools for identifying TBI, particularly in immunocompetent populations and in settings with widespread Bacillus Calmette-Guérin vaccination. In this narrative review, we synthesize current evidence on the role of IGRA within TB elimination strategies, with a focus on immunocompetent individuals. We discuss global IGRA-based estimates of TBI prevalence, the immunological principles underlying IGRA technology, and the performance of available platforms in diverse epidemiological contexts. We further examine IGRA-defined infection states, including persistent positivity, conversion, reversion, and persistent negativity, and their biological interpretation in relation to exposure intensity, host susceptibility, and progression risk. We argue that the future value of IGRA lies in its quantitative and longitudinal use within risk-adapted frameworks that integrate immune response magnitude, exposure history, and host factors. Such approaches are essential for prioritizing preventive interventions, improving efficiency of tuberculosis preventive therapy, and advancing progress toward the WHO End TB Strategy.