How to use high-sensitivity cardiac troponins in acute cardiac care

Abstract

Recommendations for the use of cardiac troponin (cTn) measurement in acute cardiac care have recently been published.¹ Subsequently, a high-sensitivity (hs) cTn T assay was introduced into routine clinical practice.² This assay, as others, called highly sensitive, permits measurement of cTn concentrations in significant numbers of apparently illness-free individuals. These assays can measure cTn in the single digit range of nanograms per litre (=picograms per millilitre) and some research assays even allow detection of concentrations 2–4 Thus, they provide a more precise calculation of the 99th percentile of cTn concentration in reference subjects (the recommended upper reference limit [URL]). These assays measure the URL with a coefficient of variation (CV) 10% at the 99th percentile URL limiting that ability.^5–7 However, the less precise cTn assays do not cause clinically relevant false-positive diagnosis of acute myocardial infarction (AMI) and a CV 8