Increasing specificity of high-sensitivity troponin: new approaches and perspectives in the diagnosis of acute coronary syndromes

Abstract

In the past years, new generations of assays to detect cardiac troponin (cTn), called sensitive or high sensitivity troponin (hs-Tn), have been introduced. Progressive improvement in the analytical sensitivity of cTn assays has led to a more rapid diagnosis of acute myocardial infarction (AMI) and improved risk stratification in patients with non ST-elevation acute coronary syndromes (NSTE-ACS) but, at the same time, has introduced the problem of a lower diagnostic specificity. As a matter of fact, hs-Tn assays are able to detect very small increases in the biomarker concentration and therefore result "positive" in a wide range of non-ischemic clinical conditions, acute and chronic, cardiac and extra-cardiac. The reduced specificity of hs-Tn versus the previous generation cTn assays may, therefore, lead to an increased number of inappropriate hospitalizations, i.e. patients with high cTn due to no-ACS conditions, and requires a more careful evaluation, not only on the clinical side, but also on the information that hs-Tn assessment may provide. Several approaches to increase this specificity have been used, but the most promising appear to be the "delta approach", which tries to quantify the relative or absolute change in cTn concentration, and the "age approach", which highlights the need for a different cutoff with a better diagnostic efficiency in the elderly population, often affected by other conditions, different from ACS, that can cause an increased level of cTn.

Keywords: Acute coronary syndrome; High sensitivity troponin; “Age approach”; “Delta approach”.