title: Performance of the AQT90 FLEX cTnI point-of-care assay for the rapid diagnosis of acute myocardial infarction in the emergency room.
abstract: BACKGROUND
  International guidelines stipulate that primarily cardiac troponin (cTn) assays with a coefficient of variation (CV) < or = 10% at the 99th percentile cutoff should be used for diagnosing myocardial infarction. Point-of-care (POC) assays usually do not meet these criteria. Here, we sought to confirm the manufacturer-recommended 99th percentile cutoff and CV of the POC assay AQT90 FLEX cTnI.
  
  
  METHODS
  119 healthy persons without cardiac disorders were examined to determine the 99th percentile cutoff and the corresponding CV. This cutoff was validated in a cohort of 80 patients with unstable angina and 71 patients with non-ST-segment elevation myocardial infarction (NSTEMI), who were admitted to a chest pain unit. cTnI concentrations were measured in serial serum samples obtained from these patients at presentation, 3 and 6 hours after admission.
  
  
  RESULTS
  A cTnI concentration of 20 ng/L was found as the 99th percentile cutoff (CV 6.7%). cTnI was > or = 20 ng/L in 51 (75%), 59 (87%), and 60 (88%) of the NSTEMI patients 0, 3 and 6 hours after admission, respectively. At admission, sensitivity was 76% and specificity 95%. Three and six hours later, sensitivity and negative predictive values increased to 88% and 98.8%, and to 92% and 97%, respectively.
  
  
  CONCLUSIONS
  We confirmed the manufacturer recommended 99th percentile cutoff of 23 ng/L and established a CV of 6.7% at 20 ng/L. These results demonstrated that the POC assay AQT90 FLEX cTnI must be classified as "guideline acceptable".
authors.forename: Boris T
authors.initials: BT
authors.lastname: Ivandic
authors.forename: Eberhard
authors.initials: E
authors.lastname: Spanuth
authors.forename: Evangelos
authors.initials: E
authors.lastname: Giannitsis
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000097:blood / Q000175:diagnosis; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis*; D019095:Point-of-Care Systems; D012372:ROC Curve; D012016:Reference Values; D015203:Reproducibility of Results; D014336:Troponin / Q000097:blood*; D055815:Young Adult
chemical_list: D014336:Troponin