Figure 3

Dual screening strategy (IGRA on all TST positive) for diagnosis of presumed latent TB infection (LTBI). Decision tree for the diagnosis of LTBI using a dual diagnostic strategy (TST in all cases followed by the T-SPOT.TB or QFT-GIT for a positive TST result). Square nodes represent decision branches, circular nodes represent chance branches and triangular nodes represent terminal branches. The same decision tree was used for both versions of the IGRA dual strategy as they both have identical screening steps in each scenario.