A common cardiac enzyme test includes: lactate dehydrogenase, alpha hydroxybutyrate dehydrogenase, creatine kinase and creatine kinase isoenzyme and costs around$50. The triple cardiac enzyme assay includes: myoglobin, troponin and creatine kinase isoenzyme and costs around$300. Myocardial enzymes are a general term for a variety of enzymes present in the myocardium, which are released when the myocardium is damaged or necrotic. The measurement of myocardial enzymes in the serum is valuable for diagnosing myocardial injury, acute myocardial infarction and evaluating the effect after thrombolysis. Myocardial enzymes can be measured at any time of the day without fasting.