title: Diagnostic delays and clinical decision making with centralized Xpert MTB/RIF testing in Durban, South Africa.
abstract: METHODS
  We conducted a retrospective study among HIV-infected adult suspects (≥18 years) with pulmonary tuberculosis (TB), who underwent Xpert MTB/RIF (Xpert) testing at McCord Hospital and its adjoining HIV clinic in Durban, South Africa.
  
  
  OBJECTIVE
  To determine if Xpert testing performed at a centralized laboratory accelerated time to TB diagnosis.
  
  
  METHODS
  We obtained data on sputum smear microscopy [acid-fast bacilli (AFB)], Xpert, and the rationale for treatment initiation from medical records. The primary outcome was "total diagnostic time," defined as time from sputum collection to clinicians' receipt of results. A linear mixed-effect model compared the duration of steps in the diagnostic pathway across testing modalities.
  
  
  RESULTS
  Among 403 participants, the median "total diagnostic time" for AFB and Xpert was 3.3 and 6.4 days, respectively (P < 0.001). When compared with AFB, the median delay for Xpert "laboratory processing" was 1.4 days (P < 0.001) and "result transfer to clinic" was 1.7 days (P < 0.001). Among 86 Xpert-positive participants who initiated treatment, 49 (57%) started treatment based on clinical suspicion or AFB-positive results, whereas only 32 (37%) started treatment based on Xpert-positive results.
  
  
  CONCLUSIONS
  In our setting, Xpert results took twice as long as AFB results to reach clinicians. Replacing AFB with centralized Xpert may delay TB diagnoses in some settings.
authors.affiliation: *Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; †Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA; ‡Division of Infectious Diseases, Department of Medicine, Brigham and Women's Hospital, Boston, MA; §Medical Practice Evaluation Center, Massachusetts General Hospital, Boston, MA; ‖The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA; ¶Tufts Clinical and Translational Science Institute, Tufts University, Boston, MA; #McCord Hospital, Durban, KwaZulu-Natal, South Africa; and **Center for AIDS Research, Harvard Medical School, Boston, MA.
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Cohen
authors.forename: Paul K
authors.initials: PK
authors.lastname: Drain
authors.forename: Farzad
authors.initials: F
authors.lastname: Noubary
authors.forename: Christie
authors.initials: C
authors.lastname: Cloete
authors.forename: Ingrid V
authors.initials: IV
authors.lastname: Bassett
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000175:diagnosis; D000328:Adult; D001426:Bacterial Proteins / Q000032:analysis; D004269:DNA, Bacterial / Q000032:analysis; D003657:Decision Making; D057210:Delayed Diagnosis; D005260:Female; D015658:HIV Infections / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D021141:Nucleic Acid Amplification Techniques / Q000379:methods*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013019:South Africa; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial