title: Value of a single troponin T at the time of presentation as compared to serial CK-MB determinations in patients with suspected myocardial ischemia.
abstract: BACKGROUND
  Prior studies with cardiac markers have focused predominantly on subjects presenting to the emergency department with chest pain or unstable angina, and have relied on serial markers for the diagnosis of acute myocardial infarction. We evaluated the diagnostic utility of a single cardiac troponin T (cTnT) determination at the time of presentation as compared to serial creatine kinase (CK) MB determinations in a broad spectrum of patients with suspected myocardial ischemia.
  
  
  METHODS
  A total of 267 consecutive patients presenting to the emergency department with suspected myocardial ischemia had a single, blinded cTnT determination drawn at the time of presentation to the emergency department in addition to routine serial electrocardiographic and CK-MB determinations.
  
  
  RESULTS
  The specificity (93.7% vs. 87.1%; p<0.05) and positive predictive value (80.0% vs. 69.4%; p<0.05) of a single cTnT determination were superior to that of serial CK-MB determinations without compromising sensitivity. Forty-six percent of patients with confirmed myocardial infarction and an abnormal cTnT at presentation had a normal initial CK-MB determination. Conversely, 20% of patients without acute coronary syndromes had an abnormal CK-MB determination in the setting of a normal cTnT. The initial cTnT was abnormal in all patients with confirmed myocardial infarction and a symptom duration of at least 3.5 h.
  
  
  CONCLUSIONS
  In a heterogeneous population of patients with suspected myocardial ischemia, the initial cTnT determination drawn at the time of presentation is a powerful diagnostic tool that, when used in context with symptom duration, allows for more rapid and accurate triage of patients than serial CK-MB determinations.
authors.affiliation: Department of Medicine, Division of Cardiology, Bridgeport Hospital, Yale University School of Medicine, New Haven, CT, USA. pszari@bpthosp.org
authors.forename: Stuart W
authors.initials: SW
authors.lastname: Zarich
authors.forename: Asad U
authors.initials: AU
authors.lastname: Qamar
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Werdmann
authors.forename: Lori S
authors.initials: LS
authors.lastname: Lizak
authors.forename: Craig A
authors.initials: CA
authors.lastname: McPherson
authors.forename: Larry H
authors.initials: LH
authors.lastname: Bernstein
mesh_terms: D000328:Adult; D000368:Aged; D000787:Angina Pectoris / Q000175:diagnosis; D003402:Creatine Kinase / Q000097:blood*; D052279:Creatine Kinase, MB Form; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis* / Q000201:enzymology; D012680:Sensitivity and Specificity; D020107:Troponin T / Q000097:blood*
chemical_list: D007527:Isoenzymes; D020107:Troponin T; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form