Prevalence of Latent Infection with Mycobacterium Tuberculosis in Interstitial Lung Diseases Using Interferon Gamma Release Assay

Introduction: The aim of this study was to evaluate the prevalence of latent tuberculosis infection (LTBI) in our interstitial lung disease (ILD) patients. Methods: Patients with ILD were tested by using a commercial test QuantiFERON®-TB-Gold In Tube (QFT) at the time of initial diagnosis, before any immunomodulatory drug was initiated. Those patients with a historical or active TB were excluded, as were any with an equivocal QFT result. They were compared with 272 control cases who had a normal chest x-rays or thoracic CT, and no history of TB. Comparisons were classified by age (