Effect of population selection on 99th percentile values for a high sensitivity cardiac troponin I and T assays

Objective: Using objective laboratory and clinical criteria to more accurately determine the 99th percentile values for cardiac troponin I and T. Design and methods: We measured cardiac troponin T and cardiac troponin I with high-sensitivity assays in a large cohort of apparently healthy community subjects and calculated 99th percentiles for different sexes and ages. Subjects with possible subclinical disease were eliminated based on objective laboratory criteria, eGFR and NT-proBNP, and clinical criteria, history and examination and echocardiogram. Results: For men and women of all ages, separately, more than 50% of subjects were excluded using these criteria, with a lesser proportion of younger subjects being excluded. In men aged <75 years, the 99th percentile for cTnI decreased by more than 50% from 22.9 ng/L to 103 ng/L. In other age groups and for cTnT the decrease was smaller (%) but still considerable. Conclusions: For establishing cardiac troponin 99th percentiles, simply using self-reporting of health is insufficient. Objective laboratory measures and clinical and echocardiographic assessments are essential to define a healthy population, especially in older persons. (C) 2013 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.