title: Ruling out acute myocardial infarction early with two serial creatine kinase-MBmass determinations.
abstract: OBJECTIVE
  We studied the diagnostic value for acute myocardial infarction of serial creatine kinase-MBmass measurements on admission and at 7 h after the onset of symptoms.
  
  
  RESULTS
  Patients presenting to our chest pain unit with symptoms of <5-h duration were eligible. Patients were kept under observation at least until 12 h after onset of symptoms. Blood samples were drawn on admission and 7 and 10 h after onset of symptoms. Creatine kinase-MBmass>7.0 microg x 1(-1) (upper reference limit for acute myocardial infarction), or an increase >2.0 microg x 1(-1) (reference change value) between admission and at 7 h was considered abnormal. Of a total of 470 patients, 248 patients had acute myocardial infarction: 100 out of the 248 patients had a single creatine kinase-MBmass>7.0 microg x 1(-1) on admission (sensitivity 40%, 95% CI:34-46%), 234/248 patients at 7 h (sensitivity 94%, 95% CI:91-97%), and 240/248 at 10 h (sensitivity 97%, 95% CI:94-99%). At 7 h, 246/248 patients had either a single creatine kinase-MB >7.0 microg x 1(-1) or a significant increase between admission and 7 h (sensitivity 99%, 95% CI:98-100%). Of 222 patients without acute myocardial infarction, 214 had a normal serial creatine kinase-MBmass (specificity 96%, 95% CI:93-98%).
  
  
  CONCLUSIONS
  In patients with symptoms of <5-h duration, acute myocardial infarction can be ruled out using serial creatine kinase-MBmass taken on admission and at 7 h.
authors.affiliation: Department of Cardiology, Academic Medical Centre, University of Amsterdam, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: de Winter
authors.forename: R
authors.initials: R
authors.lastname: Bholasingh
authors.forename: A B
authors.initials: AB
authors.lastname: Nieuwenhuijs
authors.forename: R W
authors.initials: RW
authors.lastname: Koster
authors.forename: R J
authors.initials: RJ
authors.lastname: Peters
authors.forename: G T
authors.initials: GT
authors.lastname: Sanders
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004796:Clinical Enzyme Tests; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D013997:Time Factors