title: Impact of GeneXpert MTB/RIF on patients and tuberculosis programs in a low-burden setting. a hypothetical trial.
abstract: BACKGROUND
  Guidelines recommend routine nucleic-acid amplification testing in patients with presumed tuberculosis (TB), but these tests have not been widely adopted. GeneXpert MTB/RIF (Xpert), a novel, semiautomated TB nucleic-acid amplification test, has renewed interest in this technology, but data from low-burden countries are limited.
  
  
  OBJECTIVE
  We sought to estimate Xpert's potential clinical and public health impact on empiric treatment, contact investigation, and housing in patients undergoing TB evaluation.
  
  
  METHODS
  We performed a prospective, cross-sectional study with 2-month follow-up comparing Xpert with standard strategies for evaluating outpatients for active pulmonary TB at the San Francisco Department of Public Health TB Clinic between May 2010 and June 2011. We calculated the diagnostic accuracy of standard algorithms for initial empiric TB treatment, contact investigation, and housing in reference to three Mycobacterium tuberculosis sputum cultures, as compared with that of a single sputum Xpert test. We estimated the incremental diagnostic value of Xpert, and the hypothetical reductions in unnecessary treatment, contact investigation, and housing if Xpert were adopted to guide management decisions.
  
  
  RESULTS
  A total of 156 patients underwent Xpert testing. Fifty-nine (38%) received empiric TB treatment. Thirteen (8%) had culture-positive TB. Xpert-guided management would have hypothetically decreased overtreatment by 94%, eliminating a median of 44 overtreatment days (interquartile range, 43-47) per patient and 2,169 total overtreatment days (95% confidence interval, 1,938-2,400) annually, without reducing early detection of TB patients. We projected similar benefits for contact investigation and housing.
  
  
  CONCLUSIONS
  Xpert could greatly reduce the frequency and impact of unnecessary empiric treatment, contact investigation, and housing, providing substantial patient and programmatic benefits if used in management decisions.
authors.affiliation: 1 Division of Pulmonary and Critical Care Medicine and.
authors.forename: J Lucian
authors.initials: JL
authors.lastname: Davis
authors.forename: L Masae
authors.initials: LM
authors.lastname: Kawamura
authors.forename: Lelia H
authors.initials: LH
authors.lastname: Chaisson
authors.forename: Jennifer
authors.initials: J
authors.lastname: Grinsdale
authors.forename: Jihane
authors.initials: J
authors.lastname: Benhammou
authors.forename: Christine
authors.initials: C
authors.lastname: Ho
authors.forename: Anna
authors.initials: A
authors.lastname: Babst
authors.forename: Houmpheng
authors.initials: H
authors.lastname: Banouvong
authors.forename: John Z
authors.initials: JZ
authors.lastname: Metcalfe
authors.forename: Mark
authors.initials: M
authors.lastname: Pandori
authors.forename: Philip C
authors.initials: PC
authors.lastname: Hopewell
authors.forename: Adithya
authors.initials: A
authors.lastname: Cattamanchi
mesh_terms: D000328:Adult; D000904:Antibiotics, Antitubercular / Q000191:economics / Q000627:therapeutic use; D016358:Contact Tracing; D017281:Cost of Illness; D003430:Cross-Sectional Studies; D005189:False Positive Reactions; D005260:Female; D006798:Housing / Q000191:economics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D021141:Nucleic Acid Amplification Techniques; D011446:Prospective Studies; D018570:Risk Assessment; D012495:San Francisco; D012680:Sensitivity and Specificity; D014218:Triage; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy / Q000191:economics / Q000453:epidemiology; D019564:Unnecessary Procedures / Q000191:economics / Q000706:statistics & numerical data
chemical_list: D000904:Antibiotics, Antitubercular
keywords: diagnosis; health care quality assurance; operations research; public health; tuberculosis