title: An algorithm for rule-in and rule-out of acute myocardial infarction using a novel troponin I assay.
abstract: To derive and validate a hybrid algorithm for rule-out and rule-in of acute myocardial infarction based on measurements at presentation and after 2 hours with a novel cardiac troponin I (cTnI) assay.
  
  
  
  The algorithm was derived and validated in two cohorts (605 and 592 patients) from multicentre studies enrolling chest pain patients presenting to the emergency department (ED) with onset of last episode within 12 hours. The index diagnosis and cardiovascular events up to 30 days were adjudicated by independent reviewers.
  
  
  
  In the validation cohort, 32.6% of the patients were ruled out on ED presentation, 6.1% were ruled in and 61.3% remained undetermined. A further 22% could be ruled out and 9.8% ruled in, after 2 hours. In total, 54.6% of the patients were ruled out with a negative predictive value (NPV) of 99.4% (95% CI 97.8% to 99.9%) and a sensitivity of 97.7% (95% CI 91.9% to 99.7%); 15.8% were ruled in with a positive predictive value (PPV) of 74.5% (95% CI 64.8% to 82.2%) and a specificity of 95.2% (95% CI 93.0% to 96.9%); and 29.6% remained undetermined after 2 hours. No patient in the rule-out group died during the 30-day follow-up in the two cohorts.
  
  
  
  This novel two-step algorithm based on cTnI measurements enabled just over a third of the patients with acute chest pain to be ruled in or ruled out already at presentation and an additional third after 2 hours. This strategy maximises the speed of rule-out and rule-in while maintaining a high NPV and PPV, respectively.
authors.affiliation: Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala, University, Uppsala, Sweden.
authors.forename: Bertil
authors.initials: B
authors.lastname: Lindahl
authors.affiliation: Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden.|Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Tomas
authors.initials: T
authors.lastname: Jernberg
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Patrick
authors.initials: P
authors.lastname: Badertscher
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Jasper
authors.initials: J
authors.lastname: Boeddinghaus
authors.affiliation: Department of Medical Sciences and Uppsala Clinical Research Center, Uppsala, University, Uppsala, Sweden.
authors.forename: Kai M
authors.initials: KM
authors.lastname: Eggers
authors.affiliation: Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Frick
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.|Pneumology Department, Parc de Salut Mar-IMIM-UPF, Parc de Salut Mar, Spain.|Emergency Department, Parc de Salut Mar, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Rubini Gimenez
authors.affiliation: Department of Cardiology, Danderyd University Hospital, Stockholm, Sweden.
authors.forename: Rickard
authors.initials: R
authors.lastname: Linder
authors.affiliation: Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Ljung
authors.affiliation: Capio St Görans Hospital, Stockholm, Sweden.
authors.forename: Arne
authors.initials: A
authors.lastname: Martinsson
authors.affiliation: Department of Medicine, Karolinska Institutet, Huddinge, Sweden.|Department of Cardiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Dina
authors.initials: D
authors.lastname: Melki
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nestelberger
authors.affiliation: Department of Laboratory Medicine, University Hospital Basel, Basel, Switzerland.
authors.forename: Katharina
authors.initials: K
authors.lastname: Rentsch
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Tobias
authors.initials: T
authors.lastname: Reichlin
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Sabti
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Marie
authors.initials: M
authors.lastname: Schubera
authors.affiliation: Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden.|Department of Emergency Medicine, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Per
authors.initials: P
authors.lastname: Svensson
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Raphael
authors.initials: R
authors.lastname: Twerenbold
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Karin
authors.initials: K
authors.lastname: Wildi
authors.affiliation: Department of Cardiology and Cardiovascular Research Institute Basel (CRIB), University Hospital Basel, Basel, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Mueller
mesh_terms: D000368:Aged; D000465:Algorithms; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D004562:Electrocardiography; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D019210:Troponin I / Q000097:blood*
chemical_list: D015415:Biomarkers; D019210:Troponin I