How we can utilize the Xpert MTB/RIF assay to decide on airborne infection isolation of inpatients with tuberculosis suspicion in Brazil: a brief review of the current data.

Nowadays, for prevention of tuberculosis (TB) transmission at health care facilities, the patient with a presumptive diagnosis of infectious active TB requires airborne infection isolation (AII) until three negative respiratory specimens 8–24 h apart (acid-fast bacilli strategy). However, with the current use of rapid molecular assay, Xpert MTB/RIF assay® (Xpert, Cepheid, Sunnyvale, California), an update of this recommendation is necessary. Few studies have addressed this specific issue, the majority of them performed in the United States. In a study using a decision analysis model, associated with primary data on costs and outcomes, the Xpert MTB/RIF assay to guide triage of inpatients with presumed pulmonary TB observed a cost reduction of AII by $2278 per inpatient admission.1 Another observational cohort study with 207 inpatients demonstrated that all strategies based on Xpert resulted on reduction of AII duration when compared with AFB management.2 In a prospective observational study, including 142 admissions, the comparison between serial sputum microscopy and a single Xpert MTB/RIF for triage of patients for AII, resulted in identical sensitivity and negative predictive value, 89% and 99%, respectively.3 The clinical trial “ACTG A5295/TBTC 34” showed that one or two Xperts MTB/RIF assay were each significantly more sensitive and specific than three AFB smears for identifying culture positive patients.4 In February 2015, based on an independent analysis of “ACTG A5295/TBTC 34”, the US Food Drug and Administration approved the expansion the Xpert MTB/RIF assay for AII definition in the United States based on the negative predictive value of one or two specimen Xpert strategy for absence of MTB-complex on AFB smears were 99.7% and 100%, respectively.5 To date we are not aware of specific published recommendation of Xpert-strategy for AII definition in Brazil. The data herein briefly reviewed is indicative of the approach of using one or two Xpert MTB/RIF to replace the AFB strategy for discontinuation of airborne infection isolation of patients with presumed pulmonary TB at Brazilian health care facilities.