The global priorities for tuberculosis (TB) care and control are to improve case-detection and to detect cases earlier, including cases of smear-negative disease which are often associated with coinfection with the human immunodeficiency virus (HIV) and young age, and to enhance the capacity to diagnose multidrug-resistant tuberculosis (MDR-TB). In September 2010, the World Health Organization (WHO) convened an Expert Group to review the evidence on the accuracy of the Xpert MTB/RIF assay (Cepheid, Sunnyvale, CA, United States) for the purpose of formulating recommendations to guide the use of the test. Policy recommendations on using Xpert MTB/RIF were issued by WHO early in 2011, supported by an operational how-to document and a checklist for implementation at the country level.
WHO's current policies and guidance recommend that Xpert MTB/RIF be used as an initial diagnostic test in individuals suspected of having MDR-TB or HIV-associated TB (strong recommendation, moderate quality of evidence). The guidance also provides a conditional recommendation that Xpert MTB/RIF be used as a follow-on test to smear microscopy in settings where MDR-TB or HIV are of lesser concern, especially for further testing of smear-negative specimens. In acknowledgement of the difficulties of obtaining microbiological confirmation of the diagnosis in children, this recommendation generalizes from data on adults to include the use of Xpert MTB/RIF in children.
Since 2010, more than 85 peer-reviewed research papers have been published on using Xpert MTB/RIF to diagnose pulmonary, extrapulmonary and paediatric TB, and studies continue to be performed. Given the amount of additional data on Xpert MTB/RIF that have emerged since 2010, an update of WHO's policies and guidance was warranted. WHO's Global TB Programme therefore commissioned three systematic reviews to update and revise the guidance; these reviews examined the utility of Xpert MTB/RIF in diagnosing TB and rifampicin resistance in pulmonary, extrapulmonary and paediatric TB. Published studies on the affordability and cost effectiveness of Xpert MTB/RIF were also reviewed. WHO convened an Expert Group to review the evidence at Les Pensierès, Veyrier-du-Lac, France during 20–21 May 2013. The major findings and recommendations of this Expert Group are summarized below, and a detailed meeting report is available at: http://www.who.int/tb/laboratory/policy_statements/en/
Revision of Automated real-time nucleic acid amplification technology for rapid and simultaneous detection of tuberculosis and rifampicin resistance: Xpert MTB/RIF system. Policy statement. Geneva, World Health Organization, 2011.
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