Cost-effectiveness of interferon-γ release assay versus chest X-ray for tuberculosis screening of employees

Background: Currently, an annual chest X-ray examination (CXR) for detection of active tuberculosis (TB) in employees aged >= 40 years is recommended in the guidelines of the Japan Industrial Safety and Health Law. Interferon-gamma release assays are new alternatives to the tuberculin skin test for detecting Mycobacterium tuberculosis infection, with higher specificity than the tuberculin skin test and without cross-reactivity with the Bacille Calmette-Guerin vaccine. This study aimed to assess the cost-effectiveness of employee TB screening using QuantiFERON-TB Gold In-Tube (QFT) versus CXR. Methods: Markov models were constructed. The target population was a hypothetical cohort of immunocompetent 40-year-old individuals, using a societal perspective and a lifetime horizon. All costs and clinical benefits were discounted at a fixed annual rate of 3%. Results: In a base-case analysis, the QFT strategy was the most cost-effective ($US 262.84; 22.87049 quality-adjusted life-years [QALYs]) compared with no screening ($448.38; 22.85452 QALYs) and CXR ($543.50; 22.85453 QALYs) [year 2009 values]. Conclusion: The QFT strategy is currently robust for screening Bacille Calmette-Guerin-vaccinated employees in Japan. There appears to be little role for CXR. These findings may be applicable to other countries in terms of choosing optimal TB screening for employees.