Cost effectiveness of the NICE guidelines for screening for latent tuberculosis infection: the Quantiferon-TB gold IGRA alone is more cost effective for immigrants from high burden countries.
Thorax. 2009 Dec 8. [Epub ahead of print]
Hardy AB, Varma R, Collyns T, Moffitt SJ, Mullarkey C, Watson JP.
Leeds Teaching Hospitals NHS Trust, Leeds, United Kingdom.
NICE guidelines for new entrant tuberculosis (TB) screening recommend chest X-ray (CXR) for immigrants from countries with TB incidence >40/105, and tuberculin skin test (TST) for people with normal CXR from very high TB prevalence countries. We piloted a revised screening policy using first-line QuantiFERON-TB Gold (QFT) in high risk immigrants in 2007. Initially, TST was offered to immigrants from countries with TB incidence 200-339/105, and QFT to those from countries with incidence >340/105. When increased resources became available, all immigrants from countries with TB incidence >200/105 had QFT. Those with positive QFT were invited for CXR. 1336 immigrant were invited for screening with a 32% attendance rate. 280 patients had QFT of which 38% were positive, with <2% being indeterminate. Using the NICE approach the cost of screening these 280 immigrants would be £13,346.75 (£47.67 per immigrant) and would identify 83 cases of latent TB infection (LTBI). Using first line QFT followed by CXR the cost was £9,781.82 (£34.94 per immigrant) and identified 105 LTBI. The cost to identify one case of LTBI following NICE guidelines would be £160.81 and using our protocol was £93.16. For immigrants from high risk countries QuantiFERON-TB Gold blood testing followed by CXR is feasible for TB screening, cheaper than screening using the NICE guideline and identifies more cases of LTBI.
