title: Drug susceptibility testing proficiency in the network of supranational tuberculosis reference laboratories.
abstract: METHODS
  The network of supranational tuberculosis reference laboratories (SRLs).
  
  
  OBJECTIVE
  To evaluate the annual SRL Rounds 6-14 of proficiency testing for first-line drug susceptibility testing (DST).
  
  
  METHODS
  Panels consisted of 20-30 cultures (including 10 pairs of duplicate strains), aiming at 50% resistance prevalence with a variety of profiles. The 27 SRLs participating in at least one of these rounds were free to use their preferred DST method. A judicial gold standard of at least 80% concordant 'susceptible' or 'resistant' was used to determine sensitivity, specificity and efficiency; otherwise the strain was excluded.
  
  
  RESULTS
  Of 600 strains, 10% were excluded from evaluation. The average SRL sensitivity and specificity varied between rounds, without attaining significance or trends. Both sensitivity and specificity remained at >95% for isoniazid (INH), rifampicin (RMP) and streptomycin and at >80% for ethambutol. The 16 SRLs participating in all rounds performed consistently better.
  
  
  CONCLUSIONS
  The rounds succeeded in comparing the proficiency of laboratories, and should be further promoted for DST quality assessment. However, to function with greater precision and to ultimately improve the clinical relevance of DST, the INH and RMP judicial result gold standard also needs to take into account genotypic and treatment outcome information.
authors.affiliation: International Union Against Tuberculosis and Lung Disease, Paris, France. avandeun@theunion.org
authors.forename: A
authors.initials: A
authors.lastname: Van Deun
authors.forename: A
authors.initials: A
authors.lastname: Wright
authors.forename: M
authors.initials: M
authors.lastname: Zignol
authors.forename: K
authors.initials: K
authors.lastname: Weyer
authors.forename: H L
authors.initials: HL
authors.lastname: Rieder
mesh_terms: D000995:Antitubercular Agents / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D006801:Humans; D007753:Laboratories / Q000592:standards; D008826:Microbial Sensitivity Tests / Q000592:standards; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000254:growth & development; D015588:Observer Variation; D011237:Predictive Value of Tests; D011785:Quality Assurance, Health Care / Q000592:standards; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014376:Tuberculosis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D018088:Tuberculosis, Multidrug-Resistant / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology
chemical_list: D000995:Antitubercular Agents