Cost-effectiveness of interferon-γ release assay testing for the treatment of latent tuberculosis

Abstract
The aim of the present study was to assess the cost-effectiveness of the new T-SPOT.TBassayversusthe tuberculin skin test (TST) for screening contacts for latent tuberculosis (TB) infection in Switzerland.Health and economic outcomes of isoniazid treatment of 20- and 40-yr-old close contacts were compared in a Markov model over a 20-yr period following screening with TST only (at three cut-off values) and T-SPOT.TBalone or in combination with the TST.T-SPOT.TB-based treatment was cost-effective at \#8342;11,621 and \#8342;23,692 per life-year-gained (LYG) in the younger and older age group, respectively. No TST-based programmes were cost-effective, except at a 15-mm cut-off in the younger group only, where the cost-effectiveness (\#8342;26,451·LYG−1) fell just below the willingness-to-pay threshold. Combination of the TST with T-SPOT.TBslightly reduced the total cost compared with the T-SPOT.TBalone by 4.4 and 5.0% in the younger and older groups respectively. The number of contacts treated to avoid one case of TB decreased from 50 (95% confidence interval 32–106) with the TST (10-mm cut-off) to 18 (95%CI 11–43) if T-SPOT.TBwas used.Using T-SPOT.TBalone or in combination with the tuberculin skin test for screening of close contacts before latent tuberculosis infection treatment is highly cost-effective in reducing the disease burden of tuberculosis.