Latent tuberculosis infection in a military setting diagnosed by whole-blood interferon-gamma assay

BACKGROUND AND OBJECTIVES: Rapid and accurate diagnosis of latent tuberculosis infection (LTBI) is crucial in military settings. This study aimed to detect the prevalence of LTBI using a whole-blood interferon-gamma assay based on Mycobacterium tuberculosis-specific antigens, and to identify risk factors for LTBI among military personnel in contact with patients with active pulmonary TB. METHODS: This prospective study investigated contacts in military camps in South Korea of soldiers with active pulmonary TB. The whole-blood interferon-gamma assay was performed using QuantiFERON TB-Gold. RESULTS: Among the 175 contacts, 25 (14.3%) showed positive results to the assay. Long duration of exposure (OR 2.83; 95% CI: 1.63-4.91), laryngeal TB (OR 6.04; 95% CI: 1.54-23.67) and intensive exposure (OR 5.13; 95% CI: 1.63-16.12) were associated with a positive result. CONCLUSIONS: A relatively small number of TB contacts in a military setting had LTBI.