The main difference between creatine kinase and creatine kinase isoenzyme is that creatine kinase is a general term that includes creatine kinase isoenzyme in an inclusive relationship. In clinical practice, creatine kinase isoenzyme is more specific than creatine kinase in the diagnosis of myocarditis or myocardial infarction, because there are many factors that can lead to an increase in creatine kinase, such as rhabdomyolysis, myocardial injuries, over-exercise, fever, tumors, and severe infections, all of which may lead to an increase in creatine kinase. If a patient has an elevated creatine kinase isoenzyme, it often represents some degree of myocardial injury. In addition to this, creatine kinase isoenzyme helps to predict roughly how much myocardial necrosis is present, which is what distinguishes the two.