Latent Tuberculous Infection

Abstract

without clinical evidence ofactive disease but is at risk of reactivation. Targeted tuberculin skintesting and treatment of LTBI are an integral component of the TBElimination Strategy of the U.S. Public Health Service and is a commonclinical question encountered by the primary care provider. There are fourmajor steps in the effective management of screening and treating LTBI:1. Screening at-risk populations2. Ruling-out active TB3. Weighing benefits of treatment against risk of toxicity4. Monitoring periodically and encouraging complianceThe task begins with a targeted approach for screening at-risk popula-tions. Recent guidelines have recognized the poor positive-predictivevalue of tuberculin skin testing in populations with a low prevalence ofTB and routine skin testing is not recommended. Patients at high risk forprogressing to active TB have either been infected recently (within 2years) or have concurrent medical conditions that place them at increasedrisk of reactivation of a LTBI, as summarized in Table 1. The presump-tion should be to treat those patients that are in the targeted at-riskpopulation groups with a positive screening test unless they are atsignificant risk of complications to treatment. In addition, contacts of anactive TB patient who are children 5 years, HIV-infected, or immuno-suppressed should have active TB excluded and be started on LTBItreatment regardless of their initial screening test result.