IFNG and tuberculosis: In addition to the well-recognised limitations of an IGRA (interferon-gamma release assay) in predicting risk of progression to active TB [17], some participants reported an anxiety regarding the overlap of symptoms between active TB and drug use/withdrawal (e.g. cough, sweating) and the increased likelihood of abnormal radiology due to increased rates of smoked drug use (e.g. crack lung) and cigarette smoking in this population: “they’ve got dodgy chest x-rays, they all have a cough, so they’re going to need a bit of thinking about before you whack them on some latent treatment” (#16).