IFNG and tuberculosis: QuantiFERON-TB Plus (QFT-P; Qiagen) is an ELISA-based IFN-γ release assay (IGRA) that tests for exposure to M. tuberculosis. While it is useful for the triage of suspected TB patients, it cannot discriminate between active and latent TB (12) and has shown little clinical relevance for TB treatment monitoring so far (10).