Several LTBI diagnostic strategies (screening with CXR and follow-up of inactive TB, screening with TST, screening with TST followed by confirmation with Interferon gamma release assay - IGRA, screening with single step IGRA) were compared with each other and/or with different non-LTBI screening strategies including no screening, screening for active TB with CXR, and close-contact investigation (Table 1). This evidence concerns the gene IFNG and tuberculosis.