title: Implementing the Xpert® MTB/RIF Diagnostic Test for Tuberculosis and Rifampicin Resistance: Outcomes and Lessons Learned in 18 Countries.
abstract: BACKGROUND
  The Xpert® MTB/RIF (Xpert) is an automated molecular test for simultaneous detection of tuberculosis (TB) and rifampicin resistance, recommended by the World Health Organization as the preferred diagnostic method for individuals presumed to have multi-drug resistant TB (MDR-TB) or HIV-associated TB. We describe the performance of Xpert and key lessons learned during two years of implementation under routine conditions in 33 projects located in 18 countries supported by Médecins Sans Frontières across varied geographic, epidemiological and clinical settings.
  
  
  METHODS
  Xpert was used following three strategies: the first being as the initial test, with microscopy in parallel, for all presumptive TB cases; the second being only for patients at risk of MDR-TB, or with HIV- associated TB, or presumptive paediatric TB; and the third being as the initial test for these high-risk patients plus as an add-on test to microscopy in others. Routine laboratory data were collected, using laboratory registers. Qualitative data such as logistic aspects, human resources, and tool acceptance were collected using a questionnaire.
  
  
  RESULTS
  In total, 52,863 samples underwent Xpert testing from April 2011 to December 2012. The average MTB detection rate was 18.5%, 22.3%, and 11.6% for the three different strategies respectively. Analysis of the results on samples tested in parallel showed that using Xpert as add-on test to microscopy would have increased laboratory TB confirmation by 49.7%, versus 42.3% for Xpert replacing microscopy. The main limitation of the test was the high rate of inconclusive results, which correlated with factors such as defective modules, cartridge version (G3 vs. G4) and staff experience. Operational and logistical hurdles included infrastructure renovation, basic computer training, regular instrument troubleshooting and maintenance, all of which required substantial and continuous support.
  
  
  CONCLUSIONS
  The implementation of Xpert was feasible and significantly increased TB detection compared to microscopy, despite the high rate of inconclusive results. Xpert implementation was accompanied by considerable operational and logistical challenges. To further decentralize diagnosis, simpler, low-cost TB technologies well-suited to low-resource settings are still urgently needed.
authors.affiliation: Médecins Sans Frontières, Institute of Tropical Medicine, Antwerp, Belgium.|Médecins Sans Frontières, Paris, France.
authors.forename: Elisa
authors.initials: E
authors.lastname: Ardizzoni
authors.affiliation: Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Fajardo
authors.affiliation: Médecins Sans Frontières, Southern Africa Medical Unit, Cape Town, South Africa.
authors.forename: Peter
authors.initials: P
authors.lastname: Saranchuk
authors.affiliation: Médecins Sans Frontières, Geneva, Switzerland.
authors.forename: Martina
authors.initials: M
authors.lastname: Casenghi
authors.affiliation: Epicentre, Médecins Sans Frontières, Paris, France.
authors.forename: Anne-Laure
authors.initials: AL
authors.lastname: Page
authors.affiliation: Médecins Sans Frontières, Paris, France.
authors.forename: Francis
authors.initials: F
authors.lastname: Varaine
authors.affiliation: Médecins Sans Frontières, Amsterdam, Netherlands.
authors.forename: Cara S
authors.initials: CS
authors.lastname: Kosack
authors.affiliation: Médecins Sans Frontières, Manson Unit, London, United Kingdom.
authors.forename: Pamela
authors.initials: P
authors.lastname: Hepple
mesh_terms: D000328:Adult; D002648:Child; D003955:Diagnostic Tests, Routine; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D006801:Humans; D011933:Reagent Kits, Diagnostic; D012293:Rifampin / Q000494:pharmacology / Q000627:therapeutic use*; D012307:Risk Factors; D013183:Sputum / Q000382:microbiology; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy*
chemical_list: D011933:Reagent Kits, Diagnostic; D012293:Rifampin