Objective: To evaluate the cost-effectiveness of the tuberculin skin test (TST), the QuantiFERON-TB Gold test (QFT) and a combination of TST and QFT (TST+QFT) for diagnosing latent tuberculosis infection (LTBI) in France in a bacille Calmette-Guérin (BCG) vaccinated population.
Methods: A decision analysis model evaluated three strategies among simulated adults in close contact with tuberculosis (TB). We calculated direct lifetime medical costs, life expectancies and incremental cost-effectiveness ratios (ICERs).
Results: The discounted direct medical costs of care per patient of no testing, TST, QFT and TST+QFT were respectively euro417, euro476, euro443 and euro435, while discounted life expectancies were respectively 25.030, 25.071, 25.073 and 25.062 years. TST had higher costs and lower efficacy than QFT; TST+QFT was associated with an ICER of euro560 per year of life gained (YLG) compared to no testing, and QFT was associated with an ICER of euro730/YLG compared to TST+QFT. The only scenario where QFT was associated with an ICER of >euro75 000/YLG was when the prevalence of LTBI around TB was low (<5%) and TST specificity high (>90%).
Conclusions: In France, for the diagnosis of LTBI after close contact with TB, the TST is more expensive and less effective than QFT. Although it is more expensive, QFT is more effective and cost-effective than TST+QFT under a wide range of realistic test performance scenarios.