Treatment with anti-tumor necrosis factor (TNF) agents is recognized as a risk factor for tuberculosis (TB) in patients with immune-mediated inflammatory diseases such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriatic arthritis and psoriasis. Most TB cases develop as a result of reactivation of a latent TB infection, and health authorities worldwide recommend screening for latent TB and treating patients before initiating anti-TNF treatment.