TUBERCULOSIS The QuantiFERON Ò -TB-GOLD Assay for Tuberculosis Screening in Healthcare Workers: A Cost-Comparison Analysis Benjamin D. Fox • Mordechai R. Kramer • Zohar Mor • Rachel Preiss • Victoria Rusanov • Leonardo Fuks • Nir Peled • Ilanit Haim • Meir Raz • David Shitrit Received: 14 June 2009 / Accepted: 14 September 2009 / Published online: 15 October 2009 Ó Springer Science+Business Media, LLC 2009 Abstract The aim of this study was to assess the costs of screening healthcare workers (HCWs) for tuberculosis (TB) using the novel interferon-c release assay Quanti- FERON Ò -TB Gold In-tube (QFT) versus the tuberculin skin test (TST). We used a prospective observational study with a cost-comparison analysis. The study was conducted at a regional center for ambulatory TB treatment. The study included 100 Israeli HCWs who were referred for routine TB screening. The participants were tested with both TST and QFT. For the TST, induration of 10 mm or more was considered a positive test. For the QFT, a threshold of 0.35 IU/ml interferon-c above background levels was a positive test. We developed a computerized model of the present TST-only screening method versus the QFT either alone (instead of the TST) or as a confirmatory test for a positive TST. Of the 100 subjects, 34 had a positive TST result and 17 had a positive QFT result. There was poor agreement between the TST and the QFT (j = 0.19). Assuming adherence to treatment of 50%, costs were minimized by using the QFT to confirm a positive TST (€4155). The QFT-only model was cheaper than the TST- only model (€7280 vs. €8217, respectively). The QFT-only method required the fewest clinic visits (121) compared to the TST (344). Adherence to treatment in the QFT-positive group was 47% compared with 12% for the TST-positive group. Screening HCWs with the QFT test compared to the TST resulted in fewer possible cases being identified, lower costs, and increased adherence to treatment. Costs were minimized by using the QFT to confirm a positive TST. A QFT-based screening program for HCWs is feasible and should be evaluated systematically. Keywords Costs and cost analysis Á Interferon c Á Latent tuberculosis infection Á Tuberculin test Á Healthcare worker Introduction Tuberculosis (TB) remains one of the world’s most important infectious diseases, with an estimated one-third of the world’s population infected. Following exposure to Mycobacterium tuberculosis, most infections remain latent, with late reactivation occurring usually due to reduction in host immunity [1, 2]. Identifying people with latent tuberculosis infection (LTBI) is a priority in disease con- trol, especially in developed countries where the incidence of TB disease is declining. The gold-standard screening method for LTBI is the tuberculin skin test (TST) [1]. The TST has several limitations, including the need for repeat visits and trained staff in addition to limited validity of the results [1, 3, 4]. False-positive results commonly occur in people previously vaccinated with the Bacille-Camille- Gue ´rin (BCG) vaccine and in individuals exposed to non- tuberculous mycobacteria [1, 3, 4]. B. D. Fox (&) Á R. Preiss Á V. Rusanov Á L. Fuks Á N. Peled Á I. Haim Á M. Raz Á D. Shitrit Tuberculosis Center, Maccabi Health Services, 32 Aharoni Street, Rehovot 76282, Israel e-mail: benfox@post.tau.ac.il B. D. Fox Á M. R. Kramer Á V. Rusanov Á L. Fuks Á N. Peled Á D. Shitrit Pulmonary Institute, Rabin Medical Center, Beilinson Campus, Petach Tiqwa, Israel B. D. Fox Á M. R. Kramer Á D. Shitrit Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel Z. Mor Ministry of Health, Ramle District, Israel 123 Lung (2009) 187:413–419 DOI 10.1007/s00408-009-9182-2