Cost-effectiveness of interferon-gamma release assay for entry tuberculosis screening in prisons

The incidence of active tuberculosis (TB) and latent tuberculosis infection (LTBI) in inmates and prison staff is higher than that in the general population. Mycobacterium tuberculosis-specific interferon-gamma release assays (IGRAs) provide more accurate diagnosis of M. tuberculosis infection with higher specificity than the tuberculin skin test (TST). To assess the cost effectiveness of QuantiFERON®-TB Gold In-Tube (QFT) compared to TST, TST followed by QFT and chest X-ray, we constructed Markov models using a societal perspective on the lifetime horizon. The main outcome measure of effectiveness was quality-adjusted life-years (QALYs) gained. The incremental cost-effectiveness was compared. The QFT-alone strategy was the most cost-effective for entry TB screening in prisons in developed countries. Cost-effectiveness was not sensitive to the rates of BCG vaccination, LTBI, TB, HIV infection and multidrug-resistant TB. Entry TB screening using an IGRA in prisons should be considered on the basis of its cost-effectiveness by public health intervention.