Screening for latent infection with Mycobacterium tuberculosis (LTBI) and treatment of test-positives is the cornerstone in the prevention of TB and should be performed preferably among individuals with risk for progression.
Progression from LTBI to active TB is highest in recent contacts of patients with active TB. Moreover, it is considered particularly high in latently infected patients if they are also immunodeficient. Therefore, screening for evidence of LTBI is recommended for HIV-infected individuals, patients with chronic renal failure, individuals receiving immunosuppressive drug therapy following solid organ or stem cell transplantation, and patients with autoimmune diseases.1 2 Since by definition LTBI lacks the gold standard of bacteriological confirmation, the condition is diagnosed indirectly by detection of an immune response towards mycobacterial antigens with either the tuberculin skin test (TST) or interferon- release assays (IGRA) performed from whole blood. IGRA may have test-intrinsic and operational advantages over...
