Schematic of Decision Analysis Model for Cost-Effectiveness Evaluation. Simplified schematic of decision-analysis model. Target population consists of TST-positive referrals to BCHD. LTBI prevalence among this population was estimated based on QFT-GIT positivity rates at BCHD. The model incorporates US and foreign-born to account for different LTBI prevalence in these two populations. In the Standard Algorithm, all individuals are offered LTBI treatment. In the QFT-GIT Algorithm, all individuals receive QFT-GIT and only those that are positive are provided LTBI treatment. LTBI treatment completion rates are based on current BCHD data. Individuals with incomplete treatment were considered to have only partial treatment efficacy. It is assumed that individuals without LTBI were unable to progress to active TB disease.