New-immigrant screening for latent tuberculosis infection: Reasons for non-treatment

Introduction New immigrant screening is vital for diagnosis of active and latent TB infection (LTBI), enabling treatment and chemoprophylaxis, and reducing risk of transmisison. Since 2007, we have used QuantiFERON-TB Gold (QFT), an Interferon Gamma Release Assay, in new immigrant screening. We are aware that a proportion of patients with positive results do not receive chemoprophylaxis, though reasons for this have not previously been explored. Aims We aimed to examine the reasons for non-treatment in screening recipients with positive QFT, to identify features that would enable us to effectively target this test. Methods We reviewed all positive QFT results in new immigrant screening recipients between 2007 and 2012, and examined patient records to establish reasons for non-treatment. Results 2884 QFT results were identified between 2007 and 2012, of which 684 (23.7%) were positive. Of the positive results, 12 patients (1.8%) were diagnosed with active TB through screening, and 672 (98.2%) were diagnosed with LTBI. Of the LTBI patients, 416 (61.9%) received chemoprophylaxis. The majority (74.3%) of those not treated were aged over 35, in keeping with guidelines. Over 8% were lost to follow-up; 5.4% declined treatment due to pregnancy or breastfeeding, and a similar number declined with no specific reason given. Conclusion The most common reason for non-treatment was age, in keeping with national guidelines. However a significant proportion declined or did not receive chemoprophylaxis due to patient mobility, pregnancy and loss to follow-up. Education about TB and LTBI is crucial during the screening process to improve patient engagement and reduce loss to follow-up.