Serum marker sensitivity in the patient with acute myocardial infarction.

     Serum marker sensitivity relative to the time of onset of
chest pain in the patient with acute myocardial infarction (AMI):

ACS  acute coronary syndrome;
CAD coronary artery disease; 
CK-MB creatinephosphokinase MB fraction; 
STEMI, ST segment elevation myocardial infarction.

    For patients with a nondiagnostic ECG, early elevation of serum markers specific for of myocardial necrosis (troponin I or T) confirms a presumptive diagnosis of NSTEMI. Caution is advised, however, when a single initial serum marker level is not elevated. This single test, in the first hours following symptom onset, is too insensitive to be used to support a decision that the patient can be discharged or determine that no acute coronary event has occurred.

    Cardiac troponin (cTn) is the only cardiac marker referenced in the universal definition of MI and is used
in isolation in the most recent validated standardized decision rules for the evaluation of ACS.