[Positive interferon-gamma release assay and immunosuppression: guideline-based diagnosis and treatment of tuberculosis infection].

With the growing use of immunosuppressive therapies, clinicians are increasingly faced with the question of how to manage positive interferon-gamma release assays (IGRA). A tuberculosis infection (TBI, formerly referred to as "latent tuberculosis") is clinically silent and non-contagious but can reactivate as active tuberculosis under immunosuppressive conditions. Diagnosis involves either an IGRA or a tuberculin skin test (TST), alongside microbiological and imaging studies to exclude active disease. Screening is recommended for individuals at increased risk, including those living with human immunodeficiency virus (HIV), those in close contact with tuberculosis patients, and those scheduled to receive certain immunosuppressive treatments, as well as individuals undergoing transplantation or dialysis, or those suffering from silicosis. Preventive therapy with tuberculostatic medication markedly reduces the risk of reactivation and should ideally be initiated at least 4 weeks before starting immunosuppressive therapy.