Ledesma JR, Ma J, Zheng P, et al. - Via performing this systematic review and meta-regression analysis, researchers aimed at determining the dose-response relationship between interferon-gamma release assay (IGRA) levels and the risk of progression to active tuberculosis (TB). Searching PubMed and Embase, they identified 34 studies representing 581,956 person-years of follow-up with a total of 788 incident cases of TB for inclusion in the meta-regression analysis. Findings revealed correlation of higher levels of interferon-gamma with raised risk of progression to active tuberculosis. In the dose-response curve, a sharp increase in the risk was observed between interferon-gamma levels 0 and 5 IU/ml, after which there was continuously a moderate increase in the risk but at a slower pace until reaching about 15 IU/ml where the risk levels off. Simplification in the TB infection disease continuum was noted with the current practice of dichotomizing IGRA test. Evaluation of IGRA test results over a continuous scale could aid in recognition of people at the highest risk of progression to active TB.