title: Age-specific 99th percentile cutoff of high-sensitivity cardiac troponin T for early prediction of non-ST-segment elevation myocardial infarction (NSTEMI) in middle-aged patients.
abstract: BACKGROUND
  High-sensitivity cardiac troponin T (hs-cTnT) assay is used in the diagnosis and risk assessment of patients with symptoms of myocardial infarction. This study was undertaken to establish an age-specific 99th percentile cutoff value for hs-cTnT in Chinese population, and to evaluate its potential for early prediction of non-ST-segment elevation myocardial infarction (NSTEMI) in middle-aged patients.
  
  
  METHODS
  Troponin T levels in blood obtained from healthy Chinese adults were assayed using hs-cTnT. The distribution was plotted and 99th percentiles were determined by nonparametric statistics. Prediction performance at the conventional cutoff (14 ng/L) recommended by the Roche company was compared with the age-specific cutoff for NSTEMI in 100 middle-aged patients (40-60 years of age) with acute chest pain.
  
  
  RESULTS
  The 99th percentile for hs-cTnT was 14 ng/L for patients ≥60 years of age and 11 ng/L for those <60. Fifty of the 100 patients were finally diagnosed with NSTEMI. The age-specific 99th percentile cutoff value of 11 ng/L identified a higher number of patients with NSTEMI than the conventional 14 ng/L cutoff (46 vs. 40 patients), although the difference was not statistically significant (P = 0.084). In addition, the sensitivity of hs-cTnT increased from 80 to 92% and the negative predictive values increased from 82.4 to 91.8%.
  
  
  CONCLUSIONS
  Using 11 ng/L as a decision-making cutoff point for hs-cTnT facilitated earlier prediction of NSTEMI in middle-aged patients than the conventional 14 ng/L cutoff. Further studies are needed to confirm this finding in larger group of patients.
authors.affiliation: Department of Clinical Laboratory, Shanghai East Hospital, School of Medicine, Tongji University, Shanghai, China.
authors.forename: Lie Ying
authors.initials: LY
authors.lastname: Fan
authors.forename: Ping
authors.initials: P
authors.lastname: Yu
authors.forename: Shan Shan
authors.initials: SS
authors.lastname: Yu
authors.forename: Yu Ying
authors.initials: YY
authors.lastname: Gu
authors.forename: Ming
authors.initials: M
authors.lastname: Zong
authors.forename: Ying
authors.initials: Y
authors.lastname: Cai
authors.forename: Zhong Min
authors.initials: ZM
authors.lastname: Liu
mesh_terms: D000328:Adult; D000367:Age Factors; D044466:Asian People; D002681:China; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000000981:diagnostic imaging*; D012016:Reference Values; D020107:Troponin T / Q000097:blood*; D014463:Ultrasonography
chemical_list: D020107:Troponin T
keywords: NSTEMI; cutoff value; early prediction; hs-cTnT