The clinical need for high-sensitivity cardiac troponin assays for acute coronary syndromes and the role for serial testing

Background: Cardiac troponin is the biomarker of choice for the serologic diagnosis of acute coronary syndromes. International cardiology and laboratory medicine guidelines have suggested that the cutoff concentration be set at the 99th percentile of a healthy population, with an assay imprecision of 10% or less. Unfortunately, most commercial troponin assays do not have the sensitivity and precision to reliably detect troponin in sera of healthy subjects. Therefore, there is a need to develop troponin assays with higher sensitivity, which cannot be achieved while also improving the assay's precision. Methods and Results: Novel prototype analytical testing devices have been developed that are 5- to 10-fold more sensitive than existing commercial troponin assays. These tests should enable an earlier detection of myocardial infarction relative to the time of presentation and detect a higher percentage of emergency department chest pain patients who are at risk for short-term major adverse cardiac events. However, use of a high-sensitivity troponin assay will also result in detection of more patients who have cardiac necrosis due to a nonischemic etiology. Conclusions: Serial troponin testing will be necessary to determine the clinical significance of low levels of troponin release with use of high-sensitivity assays. Guidelines will need to be established to determine a change in troponin results that is statistically and clinically significant, and new considerations for the time interval needed between blood collections. This will enable the use of future high-sensitivity troponin assays to be more valuable.