The use of TNFalpha blockers is associated with reactivation of tuberculosis 
(TB). The previous guidelines of the Israeli Association of Rheumatology were 
based on the tuberculin skin test (TST), chest X ray and a questionnaire on 
possible previous exposure to TB. The growing use of Interferon-gamma released 
assay (IGRA) has prompted the need for an update to these guidelines. All 
patients who are candidates to receive TNFalpha blockers should be screened for 
active or Latent tuberculosis. The screening includes: Tuberculin Skin Test 
(TST), interferon-gamma release assays (IGRA), chest X-ray and a questionnaire 
about possible exposure to tuberculosis. TST > or = 10 mm is considered 
positive; TST < or = 5 is negative; in case of TST = 0, a 2-step screening is 
recommended. If TST is > or = 5 mm but < 10 mm or in heavy immunosuppressed 
patients with TST = 0, an IGRA test should be performed and the diagnosis of 
latent TB taken accordingly. If the IGRA test is indeterminate, the decision 
should be taken based on the TST and patient's characteristics. Patients with a 
TST less than 5 mm. should be questioned about prior exposure to tuberculosis. 
Latent tuberculosis should be treated with a 9 month course of isoniazid (300 
mg/d) or a 4 month course of rifampicin (600 mg/d) or for 3 months with a 
combination of 300 mg. isoniazid and 600 mg. rifampicin daily. The committee 
recommends postponing treatment with TNFalpha blockers until completion of 
anti-tuberculosis therapy. If the clinical condition requires the urgent use of 
TNFalpha blockers, these may be initiated one month after starting treatment for 
latent tuberculosis.