title: Comparison of diagnostic accuracy between three different rules of interpreting high sensitivity troponin T results.
abstract: With the introduction of high sensitivity troponin-T (hs-TnT) assay, clinicians face more patients with 'positive' results but without myocardial infarction. Repeated hs-TnT determinations are warranted to improve specificity. The aim of this study was to compare diagnostic accuracy of three different interpretation rules for two hs-TnT results taken 6 h apart. After adjusting for clinical differences, hs-TnT results were recoded according to the three rules. Rule1: hs-TnT >13 ng/L in at least one determination. Rule2: change of >20 % between the two measures. Rule3: change >50 % if baseline hs-TnT 14-53 ng/L and >20 % if baseline >54 ng/L. The sensitivity, specificity and ROC curves were compared. The sensitivity analysis was used to generate post-test probability for any test result. Primary outcome was the evidence of coronary critical stenosis (CCS) on coronary angiography in patients with high-risk chest pain. 183 patients were analyzed (38.3 %) among all patients presenting with chest pain during the study period. CCS was found in 80 (43.7 %) cases. The specificity was 0.62 (0.52-0.71), 0.76 (0.66-0.84) and 0.83 (0.74-0.89) for rules 1, 2 and 3, respectively (P < 0.01). Sensitivity decreased with increasing specificity (P < 0.01). Overall diagnostic accuracy did not differ among the three rules (AUC curves difference P = 0.12). Sensitivity analysis showed a 25 % relative gain in predicting CCS using rule 3 compared to rule 1. Changes between two determinations of hs-TnT 6 h apart effectively improved specificity for CCS presence in high-risk chest pain patients. There was a parallel loss in sensitivity that discouraged any use of such changes as a unique way to interpret the new hs-TnT results.
authors.affiliation: Department of Emergency Medicine, Catholic University of the Sacred Heart, Largo Francesco Vito 1, 00168 Rome, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Buccelletti
authors.forename: Leonarda
authors.initials: L
authors.lastname: Galiuto
authors.forename: Davide
authors.initials: D
authors.lastname: Marsiliani
authors.forename: Paolo
authors.initials: P
authors.lastname: Iacomini
authors.forename: Pierpaolo
authors.initials: P
authors.lastname: Mattogno
authors.forename: Annarita
authors.initials: A
authors.lastname: Carroccia
authors.forename: Chiara
authors.initials: C
authors.lastname: Cordischi
authors.forename: Simone
authors.initials: S
authors.lastname: Antonini
authors.forename: Elisa
authors.initials: E
authors.lastname: Fedele
authors.forename: Marta
authors.initials: M
authors.lastname: Sabbatini
authors.forename: Nicolò Gentiloni
authors.initials: NG
authors.lastname: Silveri
authors.forename: Francesco
authors.initials: F
authors.lastname: Franceschi
mesh_terms: D000368:Aged; D002637:Chest Pain; D015331:Cohort Studies; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D011237:Predictive Value of Tests; D012016:Reference Values; D012680:Sensitivity and Specificity; D013223:Statistics as Topic; D020107:Troponin T / Q000097:blood*
chemical_list: D020107:Troponin T