Interferon-Gamma Release Assay-Based Screening for Pediatric Latent Tuberculosis Infection in an Urban Primary Care Network

Objective To assess outcomes from a QuantiFERON-tuberculosis (TB) Gold (QFT)-based screening for pediatric latent TB infection (LTBI) in the Denver Health Community Health System (CHS), an urban primary-care network in the US. Study design We retrospectively analyzed all QFTs (n = 6685) performed on children aged 2-18 years between January 5, 2011, and August 18, 2014. Risk factors for positive testing in the CHS population were identified by logistic regression, and further assessed using a case-control comparison. Results from CHS were compared with higher-TB-risk populations (refugee and TB clinics) in our health system. Results Positive QFT occurred in 79 of 3745 (2.1%) CHS patients. Positive rates increased with age (0.3% in age 2-5 years to 4.9% in age 13-18 years). Indeterminate results were uncommon (0.8%) including in children Discussion QFT-based LTBI screening was successfully introduced in our pediatric primary-care health system, and supported our programmatic goals of identifying LTBI cases while limiting unnecessary LTBI treatment courses. Increasing positive rates with age, and higher rates in the refugee/TB populations compared with CHS, add indirect evidence of adequate test sensitivity, even among young children, for whom data on interferon-gamma release assay performance are limited.