Interferon-γ release assays for diagnosis of active pleural tuberculosis: a developing world perspective

We thank K. Shah and Z. Udwadia for their comment on the joint systematic review and meta-analysis of the role of interferon-c release assays (IGRAs) for the diagnosis of active tuberculosis (TB) by the Tuberculosis Network European Trials Group (TBNET) and the European Centre for Disease Prevention and Control It was demonstrated that immunodiagnosis by tuberculin skin testing and conventional IGRAs performed on cells from the peripheral blood, i.e. the QuantiFERON1-TB Gold In-Tube (Cellestis, Carnegie, Victoria, Australia) and the T-SPOT1.TB (Oxford Immunotec, Abingdon, UK) assays, has a limited role in the diagnosis of active TB. Although the sensitivities of both IGRAs in detecting active TB are higher than that of the tuberculin skin test, their sensitivities are not high enough to be used as rule-out tests for TB and their specificities are insufficient to distinguish active TB from latent infection with Mycobacterium tuberculosis.