Approach to diagnosis of tuberculosis infection (tuberculosis screening) in adults

TBI: tuberculosis infection; TB: tuberculosis; IGRA: interferon-gamma release assay; TST: tuberculin skin test.

* For indications for TBI testing, refer to the UpToDate topic on approach to diagnosis of TBI. Only those who would benefit from treatment of TBI should undergo testing, so a decision to test presupposes a decision to treat if the test is positive.

¶ If the first test is negative, close contacts (defined as individuals who share an enclosed space with a patient with untreated respiratory TB disease for ≥4 hours per week) should undergo a second test eight weeks later. Many TB programs test casual contacts only once at eight weeks after exposure.

Δ In general, either IGRA or TST may be used; IGRA is preferable if available, particularly for patients who are unlikely to return to have the TST read and for patients with a history of Bacille Calmette-Guerin (BCG) vaccination administered after 12 months of age.