False-negative interferon-γ release assay result in an elderly patient with tuberculous meningitis

Tuberculous meningitis (TBM) is the most severe manifestation of extra-pulmonary tuberculosis, and has high morbidity and mortality. Therefore early treatment, which is empirical therapy, is essential to improve the clinical prognosis of TBM. But rapid diagnosis remains a challenge due to non-specific symptoms, low sensitivity and time-comsuming diagnostic tests. Mycobacterium tuberculosis antigen specific interferon-γ release assay (IGRA) is widely considered as an adjunctive test to confirm latent tuberculous infection or to support the diagnosis of active tuberculous infection. However, elderly patients with TBM have been shown to have a higher rate of false negative IGRA results than patients with tuberculosis at other sites. We report a case of TBM with a negative IGRA test for M. tuberculosis antigen.