At the time of TB diagnosis, older adults were more likely than younger adults to have a negative interferon gamma release assay (IGRA) result (24.6% vs 16.0%, P = .01), and individuals aged 75 years and older had a higher proportion of negative IGRA results (32.9%) than those aged 65–74 years old (11.4%, P = .03) (Table 2). Here, IFNG is linked to tuberculosis.