Prospective Comparison of the Tuberculin Skin Test and Interferon-Gamma Release Assays in Diagnosing Infection With Mycobacterium Tuberculosis and in Predicting Progression to Tuberculosis

This is a prospective cohort study of persons tested for latent tuberculosis infection at either high risk for exposure to Mycobacterium tuberculosis or high risk for progression to tuberculosis disease. The study will assess the relative performance and cost of three diagnostic tests for latent tuberculosis infection (tuberculin skin test, QuantiFERON-TB Gold In-Tube, and T-SPOT.TB) and will examine the rates of positive results among the cohort. This study will also determine the risk and rate of progression to active TB disease, overall and by the results of the three tests.