Cardiac enzyme studies measure the levels of enzymes and proteins that are linked with injury of the heart muscle. These include the enzyme creatine kinase (CK), and the proteins troponin I (TnI) and troponin T (TnT). Low levels of these enzymes and proteins are normally found in your blood, but if your heart muscle is injured, such as from a heart attack, the enzymes and proteins leak out of damaged heart muscle cells, and their levels in the bloodstream rise.
Because some of these enzymes and proteins are also found in other body tissues, their levels in the blood may rise when those other tissues are damaged. Cardiac enzyme studies must always be compared with your symptoms, your physical examination findings, and electrocardiogram (EKG, ECG) results.
Cardiac enzyme studies are done to:
Determine whether you are having a heart attack or acute coronary syndrome if you have symptoms such as chest pain, shortness of breath, nausea, sweating, and abnormal electrocardiography results.
Check for injury to the heart from other causes, such as an infection.