The British Cardiac Society (BCS) Working Group on the definition of acute myocardial infarction¹ presents a pragmatic and practical nomenclature for acute coronary syndromes (ACS) and sets definite cut off points for troponin T (TnT) and troponin I (TnI).

We reviewed retrospectively the relation between TnT and creatine kinase (CK) in 978 admissions to our cardiac care unit (over a three year period) who survived to discharge. Criteria for inclusion were simple—that the final discharge diagnosis be recorded, and that patients survive to discharge and had TnT and a peak CK recorded. No attempt was made to correct for sampling time. Our aim was to establish a cut off value for TnT to be equivalent to twice our upper limit of normal for CK (2 × 190  =  380 IU). The mean TnT was 1.09 ng/ml and the mean CK was 433 IU. The correlation between the two, while significant, was not good enough to be clinically useful (fig 1). CK could range from 200–1000 IU …