Table 3.

Identification of patients at increased risk of tuberculosis.

Clinical history

Ethnicity

Prolonged exposure in countries where TB is endemic

History of contact with TB

Previous active TB and treatment given

Date of the last BCG vaccination

Physical examination

TST or IGRA

TST may be negative in patients using corticosteroids for more than 1 month

TST may be negative in patients using thiopurines or methotrexate for more than 3 months

IGRA should be used in patients with previous BCG vaccination

Chest X-ray: findings suggestive of old TB

Apical calcification

Pleural thickening

TB, tuberculosis; BCG, bacille Calmette–Guérin; TST, tuberculin skin testing; IGRA, interferon gamma-release assay.