A micro-costing of latent tuberculosis infection testing and treatment in adults in secondary care in England

BackgroundLatent TB infection (LTBI) screening and treatment of population groups at high risk for TB is part of Englands Tuberculosis Action Plan, which has succeeded in increasing testing volumes. However, analysis of the cost-effectiveness is hampered by a lack of detailed information on health service costs. MethodsWe surveyed clinics with large volumes of activity, located in the London, West Midlands, South East & South West, and North West England TB Control Board areas. These represent three-quarters of Englands TB diagnoses. We mapped clinical pathways and determined costs of staff time, testing, and drugs. ResultsThe clinics use interferon gamma release assays (IGRAs) (Quantiferon-TB Gold Plus, T-SPOT.TB, or both) for LTBI testing, and the most common outcomes of the testing pathways are asymptomatic patients testing negative (costing {pound}64.11 per patient, range: {pound}49.08-{pound}81.02) or positive (costing {pound}142.86({pound}120.95-{pound}174.68)). Symptomatic patients, testing positive or negative, have higher costs ({pound}124.35({pound}101.29-{pound}138.23)). The estimated cost per patient diagnosed with LTBI is {pound}458.32({pound}362.49-{pound}571.47). Treatment costs depend on the regimen and the amount of monitoring the patient requires, e.g. 3 months daily Isoniazid and Rifampicin costs {pound}192.68({pound}140.43-{pound}255.32) for most patients, and {pound}238.62({pound}157.47-{pound}346.03) for those requiring more monitoring. 6 months daily Isoniazid costs {pound}411.04({pound}362.56-{pound}474.25). 4 months daily Rifampicin costs {pound}226.97({pound}190.15-{pound}270.73). One clinic uses 3 months of weekly Isoniazid and Rifapentine for some patients, costing {pound}559.05. DiscussionThese are the first detailed cost estimates of latent TB screening and treatment, and will enable improved assessment of cost-effectiveness, and allocation of resources.