Diagnosis and management of latent tuberculosis

Latent tuberculosis infection (LTBI) may affect over two billion individuals and serves as a potential reservoir for future active tuberculosis. The identification and treatment of LTBI in those at highest risk for progression is an essential part of tuberculosis control.

Interferon-γ release assays are increasingly used for targeted testing and diagnosis of latent disease. The performance of these immunodiagnostic tests has been studied in various groups and may be better than the tuberculin skin test in certain populations. Ongoing research is focused on new biomarkers that may diagnose LTBI or predict progression to active tuberculosis. Isoniazid preventive treatment is effective at reducing risk of active disease, but length of treatment and potential side-effects limit patient acceptance and compliance. Rifamycin-based regimens are increasingly studied as a shorter and perhaps less toxic alternative for preventive therapy.

Identification of those with LTBI is important as it allows treatment of those at highest risk of progression to active disease and thus decreases the overall burden of tuberculosis. The development of new immunodiagnostics may further improve identification of those at risk and alternative medication regimens may increase compliance with and efficacy of preventive therapy.