title: Evaluation of a new ultrasensitive assay for cardiac troponin I.
abstract: OBJECTIVE
  We evaluated the analytical and clinical performance of a new ultrasensitive cardiac troponin I assay (cTnI) on the ADVIA Centaur system (TnI-Ultra).
  
  
  METHODS
  The evaluation included the determination of detection limit, within-assay and between-assay variation and comparison with two other non-ultrasensitive methods. Moreover, cTnI was determined in 120 patients with acute chest pain with three methods. To evaluate the ability of the new method to detect MI earlier, it was assayed in 8 MI patients who first tested negative then positive by the other methods.
  
  
  RESULTS
  The detection limit was 0.009 microg/L and imprecision was <10% at all concentrations evaluated. In comparison with two other methods, 10% of the anginas diagnosed were recategorized to MI.
  
  
  CONCLUSIONS
  The ADVIA Centaur TnI-Ultra assay presented high reproducibility and high sensitivity. The use of the recommended lower cutpoint (0.044 microg/L) implied an increased and earlier identification of MI.
authors.affiliation: Department of Biochemistry and Molecular Genetics and Core Laboratory (CDB), Hospital Clínic, C/Villaroel, 170, 08036 Barcelona, Catalonia, Spain.
authors.forename: Gregori
authors.initials: G
authors.lastname: Casals
authors.forename: Xavier
authors.initials: X
authors.lastname: Filella
authors.forename: Josep Lluis
authors.initials: JL
authors.lastname: Bedini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis; D003935:Diagnostic Techniques, Cardiovascular; D042241:Early Diagnosis; D004562:Electrocardiography; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D009206:Myocardium / Q000378:metabolism*; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000032:analysis* / Q000097:blood / Q000378:metabolism
chemical_list: D015415:Biomarkers; D019210:Troponin I