IFNG and tuberculosis: The regulatory-approved, commercially available ELISpot assay, T-SPOT.TB (Oxford Immunotec Ltd, Abingdon, UK) is based on the assay used here, developed by Lalvani.7–10 T-SPOT.TB and an alternative interferon-gamma release assay, the whole blood ELISA (QuantiFERON-Gold, Cellestis, Carnegie, Australia), have recently been approved by the National Institute for Clinical Excellence (NICE) for diagnosis of latent TB infection and as adjunctive tests for the evaluation of patients with active TB.