How do you approach ongoing screening for TB in patients with a history of treated latent TB, but who have ongoing use of DMARDs and/or biologics given Quantiferon testing and PPD can remain positive?  

Interferon-release assays (such as Quantiferon) and PPD testing do not discriminate between infection, reinfection, and prior infection with TB. However, in most developed countries, the likelihood that a patient who has once been treated for LTBI becomes reinfected and develops LTBI again is low, i...