Was it a heart attack?BMJ 2002; 324 doi: https://doi.org/10.1136/bmj.324.7347.1216 (Published 18 May 2002) Cite this as: BMJ 2002;324:1216
Troponin measurement is not straightforward
- Eric S Kilpatrick (email@example.com), consultant in chemical pathology
- Hull Royal Infirmary, Hull HU3 2JZ
- Monklands Hospital, Airdrie ML6 0JS
- Greater Glasgow NHS Board, Glasgow G3 8YU
EDITOR—McKenna and Forfar describe how the proposed redefinition of myocardial infarction has made the measurement of cardiac specific troponin central to its diagnosis.1 In a patient presenting with chest pain a troponin concentration above the 99th centile of normal is now sufficient to diagnose myocardial infarction, irrespective of any electrocardiographic changes. Previously, as the authors state, a patient had to show the development of Q waves on electrocardiography or an increase in creatine kinase activity to more than twice the upper reference limit before this judgment was made. The widespread introduction of troponin T and troponin I measurements is an undoubted improvement, but limitations exist with the assays, which most clinicians are unaware of and may give rise to diagnostic difficulties.
One issue concerns the use of the 99th centile of normal as the cut off point for myocardial infarction. Most assays are not sensitive enough to measure values as low as this. For example, the 99th centile for troponin …