Latent TB infection screening for patients preparing to receive a TNF-alpha inhibitor who have risk factors for latent TB

TB: tuberculosis; TNF: tumor necrosis factor; IGRA: interferon-gamma release assay; TST: tuberculin skin test; LTBI: latent tuberculosis infection; BCG: Bacille Calmette-Guérin.
* We prefer the IGRA over the TST as it is likely more sensitive under conditions of immunosuppression, it can be accomplished in one visit, and it eliminates the need to know a patient's BCG history (which is not always clear). In patients who have not received the BCG vaccine, the TST is a reasonable alternative to the IGRA.
¶ The two IGRAs are the QuantiFERON-TB Gold In-Tube and the T-SPOT.TB assay. When retesting, it is acceptable to use either the same IGRA or the other assay.
Δ In patients with a negative IGRA and no history of BCG vaccination, it is appropriate to check a TST. In patients with a negative IGRA and a history of BCG vaccination, we repeat the IGRA. When retesting, it is acceptable to use either the same IGRA or the other assay.
◊ The treatment of patients with a negative LTBI screening test should be made on a case-by-case basis, depending on the risk of TB exposure and the likelihood that a negative test represents a false-negative result. The same concept applies to patients with indeterminate IGRA results. Treatment for LTBI should be considered if there is a strong likelihood of prior TB exposure (eg, evidence of remote TB disease on chest radiography [eg, regional fibrosis with or without hilar lymphadenopathy], history of close contact with a TB case, or having resided in a country with high TB prevalence), especially if the patient was immunocompromised at the time of testing for LTBI.