title: Evaluation of a new assay for cardiac troponin I vs creatine kinase-MB for the diagnosis of acute myocardial infarction. Biochemical Markers for Acute Myocardial Ischemia (BAMI) Study Group.
abstract: OBJECTIVE
  To compare a new assay for cardiac troponin 1 (cTn-1) with an assay for creatine kinase-MB (CK-MB) for the diagnosis of acute myocardial infarction (AMI).
  
  
  METHODS
  A prospective cross-sectional study of patients presenting with symptoms consistent with cardiac ischemia was performed at a university teaching hospital. Serum sampling for cTn-1 and CK-MB was performed at 0, 1, 3, 8, and 16 hours after presentation. Normal values were defined as CK-MB < or = 7 ng/mL and a relative index < or = 2%, cTn-I < or = 1.4 ng/mL. Final diagnosis was made using World Health Organization criteria, including standard enzyme sampling. Consecutive patients with AMI were compared with a randomly selected subset of patients without AMI to determine the sensitivity and specificity of cTn-I and CK-MB assays for AMI, stratified by time from symptom onset. The ability of the biochemical cardiac markers obtained within 6 hours of symptom onset to predict later complications or need for interventions was assessed using odds ratios (ORs).
  
  
  RESULTS
  Thirty-five patients who had AMI were compared with 136 patients who did not have AMI. The sensitivities and specificities of the cTn-I and CK-MB assays, stratified by time from symptom onset, were: [table: see text]. Patients who had elevations in either CK-MB or cTn-I within 6 hours of symptom onset were at increased risk for cardiovascular complications and/or interventions (CK-MB, OR 5.8; cTn-I, OR 6.3).
  
  
  CONCLUSIONS
  cTn-I was as sensitive and specific for AMI as was CK-MB in ED patients who presented within 24 hours of symptom onset. However, cTn-I was more sensitive in patients who presented > or = 24 hours after symptom onset. Elevations of either marker within 6 hours of symptom onset predict an increased risk of complications and/or need for interventions.
authors.affiliation: Department of Emergency Medicine, University Medical Center, State University of New York, Stony Brook 11794-8350, USA. gbrogan@epo.som.sunysb.edu
authors.forename: G X
authors.initials: GX
authors.lastname: Brogan
authors.forename: J E
authors.initials: JE
authors.lastname: Hollander
authors.forename: C F
authors.initials: CF
authors.lastname: McCuskey
authors.forename: H C
authors.initials: HC
authors.lastname: Thode
authors.forename: J
authors.initials: J
authors.lastname: Snow
authors.forename: A
authors.initials: A
authors.lastname: Sama
authors.forename: J L
authors.initials: JL
authors.lastname: Bock
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D003402:Creatine Kinase / Q000097:blood*; D003430:Cross-Sectional Studies; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007527:Isoenzymes; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood*; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D019210:Troponin I; D003402:Creatine Kinase