Figure 2From: High background rates of positive tuberculosis-specific interferon-γ release assays in a low prevalence region of UK: a surveillance study Age specific prevalences of IGRA-positivity amongst exposed patients and amongst unexposed patients. Error bars show standard errors of the mean. a) data stratified according to four age-groups. b) data stratified by seven age groups, as per Syed et al.[2].Back to article page