RT Journal Article SR Electronic T1 Clinical chemistry score versus high-sensitivity cardiac troponin I and T tests alone to identify patients at low or high risk for myocardial infarction or death at presentation to the emergency department JF Canadian Medical Association Journal JO CMAJ FD Canadian Medical Association SP E974 OP E984 DO 10.1503/cmaj.180144 VO 190 IS 33 A1 Peter A. Kavsak A1 Johannes T. Neumann A1 Louise Cullen A1 Martin Than A1 Colleen Shortt A1 Jaimi H. Greenslade A1 John W. Pickering A1 Francisco Ojeda A1 Jinhui Ma A1 Natasha Clayton A1 Jonathan Sherbino A1 Stephen A. Hill A1 Matthew McQueen A1 Dirk Westermann A1 Nils A. Sörensen A1 William A. Parsonage A1 Lauren Griffith A1 Shamir R. Mehta A1 P.J. Devereaux A1 Mark Richards A1 Richard Troughton A1 Chris Pemberton A1 Sally Aldous A1 Stefan Blankenberg A1 Andrew Worster YR 2018 UL http://www.cmaj.ca/content/190/33/E974.abstract AB BACKGROUND: Testing for high-sensitivity cardiac troponin (hs-cTn) may assist triage and clinical decision-making in patients presenting to the emergency department with symptoms of acute coronary syndrome; however, this could result in the misclassification of risk because of analytical variation or laboratory error. We sought to evaluate a new laboratory-based risk-stratification tool that incorporates tests for hs-cTn, glucose level and estimated glomerular filtration rate to identify patients at risk of myocardial infarction or death when presenting to the emergency department.METHODS: We constructed the clinical chemistry score (CCS) (range 0–5 points) and validated it as a predictor of 30-day myocardial infarction (MI) or death using data from 4 cohort studies involving patients who presented to the emergency department with symptoms suggestive of acute coronary syndrome. We calculated diagnostic parameters for the CCS score separately using high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT).RESULTS: For the combined cohorts (n = 4245), 17.1% of participants had an MI or died within 30 days. A CCS score of 0 points best identified low-risk participants: the hs-cTnI CCS had a sensitivity of 100% (95% confidence interval [CI] 99.5%–100%), with 8.9% (95% CI 8.1%–9.8%) of the population classified as being at low risk of MI or death within 30 days; the hs-cTnT CCS had a sensitivity of 99.9% (95% CI 99.2%–100%), with 10.5% (95% CI 9.6%–11.4%) of the population classified as being at low risk. The CCS had better sensitivity than hs-cTn alone (hs-cTnI < 5 ng/L: 96.6%, 95% CI 95.0%–97.8%; hs-cTnT < 6 ng/L: 98.2%, 95% CI 97.0%–99.0%). A CCS score of 5 points best identified patients at high risk (hs-cTnI CCS: specificity 96.6%, 95% CI 96.0%–97.2%; 11.2% [95% CI 10.3%–12.2%] of the population classified as being at high risk; hs-cTnT CCS: specificity 94.0%, 95% CI 93.1%–94.7%; 13.1% [95% CI 12.1%–14.1%] of the population classified as being at high risk) compared with using the overall 99th percentiles for the hs-cTn assays (specificity of hs-cTnI 93.2%, 95% CI 92.3–94.0; specificity of hs-cTnT 73.8%, 95% CI 72.3–75.2).INTERPRETATION: The CCS score at the chosen cut-offs was more sensitive and specific than hs-cTn alone for risk stratification of patients presenting to the emergency department with suspected acute coronary syndrome. Study registration: ClinicalTrials.gov, nos. NCT01994577; NCT02355457