High sensitivity cardiac troponin in patients with chest painBMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f4222 (Published 22 July 2013) Cite this as: BMJ 2013;347:f4222
- Anoop S V Shah, clinical research fellow,
- David E Newby, professor of cardiology,
- Nicholas L Mills, reader in cardiology
- 1British Heart Foundation/University Centre for Cardiovascular Science, University of Edinburgh, Edinburgh EH16 4SU, UK
- Correspondence to: N L Mills
High sensitivity troponin assays can measure troponin in more than 50% of a normal reference population and can therefore identify people above or below the 99th centile with optimal precision (<10% coefficient of variation)
With high sensitivity troponin assays, use the 99th centile of the normal reference population as the diagnostic threshold for myocardial infarction, and consider sex specific thresholds
Measure troponin concentration on admission and three to six hours after admission, irrespective of the timing of onset of symptoms
Many conditions other than myocardial infarction, such as septicaemia, renal failure, and heart failure, increase troponin concentration
Demonstration of a rise and/or fall in troponin concentration is needed to identify patients with acute myocardial infarction
A 55 year old woman presented to the emergency department with sharp retrosternal chest pain that resolved after 30 minutes en route to the hospital. She was a cigarette smoker with no relevant past medical history or other known cardiovascular risk factors. Clinical examination and a resting electrocardiogram were unremarkable.
What is the next investigation?
Electrocardiography remains the first line diagnostic test in patients with suspected acute coronary syndrome. However, despite excellent specificity (97%) it has low sensitivity (28%),1 and diagnosis of acute myocardial infarction requires the complementary application of cardiac biomarkers.2 Troponins are regulatory muscle proteins that are released into the circulation following acute myocardial injury. Assays that quantify cardiac isoforms of troponin have greater specificity and sensitivity for the diagnosis of myocardial infarction than do traditional cardiac enzymes. Measurement of creatine kinase MB and myoglobin in patients with chest pain is no longer recommended.3
Recent advances have led to greatly improved assay sensitivity permitting quantification of extremely low concentrations of troponin with excellent precision. …