title: The health-system benefits and cost-effectiveness of using Mycobacterium tuberculosis direct nucleic acid amplification testing to diagnose tuberculosis disease in the United States.
abstract: BACKGROUND
  The utility of Mycobacterium tuberculosis direct nucleic acid amplification testing (MTD) for pulmonary tuberculosis disease diagnosis in the United States has not been well described.
  
  
  METHODS
  We analyzed a retrospective cohort of reported patients with suspected active pulmonary tuberculosis in 2008-2010 from Georgia, Hawaii, Maryland, and Massachusetts to assess MTD use, effectiveness, health-system benefits, and cost-effectiveness.
  
  
  RESULTS
  Among 2140 patients in whom pulmonary tuberculosis was suspected, 799 (37%) were M. tuberculosis-culture-positive. Eighty percent (680/848) of patients having acid-fast-bacilli-smear-positive specimens had MTD performed; MTD positive-predictive value (PPV) was 98% and negative-predictive value (NPV) was 94%. Nineteen percent (240/1292) of patients having smear-negative specimens had MTD; MTD PPV was 90% and NPV was 88%. Among patients suspected of tuberculosis but not having MTD, smear PPV for lab-confirmed tuberculosis was 77% and NPV 78%. Compared with no MTD, MTD significantly decreased time to diagnosis in patients with smear-positive/MTD-positive specimens, decreased respiratory isolation for patients having smear-positive/MTD-negative/culture-negative specimens, decreased outpatient days of unnecessary tuberculosis medications, and reduced resources expended on contact investigation. While MTD generally cost more than no MTD, incremental cost savings occurred in patients with human immunodeficiency virus (HIV) or homelessness to diagnose or to exclude tuberculosis, and in patients with substance abuse having smear-negative specimens to exclude tuberculosis.
  
  
  CONCLUSIONS
  MTD improved diagnostic accuracy and timeliness and reduced unnecessary respiratory isolation, treatment, and contact investigations. It was cost saving in patients with HIV, homelessness, or substance abuse, but not in others.
authors.affiliation: US Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. smarks@cdc.gov
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Marks
authors.forename: Wendy
authors.initials: W
authors.lastname: Cronin
authors.forename: Thara
authors.initials: T
authors.lastname: Venkatappa
authors.forename: Gina
authors.initials: G
authors.lastname: Maltas
authors.forename: Sandy
authors.initials: S
authors.lastname: Chon
authors.forename: Sharon
authors.initials: S
authors.lastname: Sharnprapai
authors.forename: Mary
authors.initials: M
authors.lastname: Gaeddert
authors.forename: Jane
authors.initials: J
authors.lastname: Tapia
authors.forename: Susan E
authors.initials: SE
authors.lastname: Dorman
authors.forename: Sue
authors.initials: S
authors.lastname: Etkind
authors.forename: Claud
authors.initials: C
authors.lastname: Crosby
authors.forename: Henry M
authors.initials: HM
authors.lastname: Blumberg
authors.forename: John
authors.initials: J
authors.lastname: Bernardo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000191:economics* / Q000379:methods*; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques / Q000191:economics* / Q000379:methods*; D012189:Retrospective Studies; D013997:Time Factors; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*; D014481:United States; D055815:Young Adult
keywords: cost; diagnosis; molecular; nucleic acid amplification; tuberculosis