The role of Xpert(®) MTB/RIF for tuberculosis (TB) diagnosis remains to be clearly delineated in high-resource settings. At a London hospital, we evaluated a policy of selective assay use, with testing restricted to defined sub-groups of patients. Management was directly influenced in 30% of patients studied, including 'ruling-in' a TB diagnosis (leading to initiation of treatment for TB or for potential multidrug-resistant TB); negative assay results also helped support decisions for cessation of empirical anti-tuberculosis treatment or the safe initiation of other treatments such as immunosuppressant drugs. The benefits and pitfalls of this assay's use within high-resource settings are discussed.