CK should be used only in the early stages of myocardial infarction. If the CK is normal shortly after onset of chest pain thought to be of myocardial origin then a repeat estimation 3—4 hours later may be helpful.
CK is less sensitive and less specific for the diagnosis of myocardial injury than Troponin I. Skeletal muscle CK is elevated in several situations, e.g. post–operatively, after intramuscular injections, following trauma or vigorous exercise, and in some diseases of skeletal muscle. |