Normal cardiac enzyme levels are between 0 and 3 for creatine kinase, between 0 and 3 nanograms per millimeter for creatine kinase-MB, less than 0.4 nanograms per millimeter for troponin and 38-120 nanograms per millimeter for total creatine kinase, according to the University of Minnesota. These levels are checked during a cardiac enzyme study to diagnose injuries to a patient's heart muscle, according to WebMD.
Creatine kinase is an enzyme, while troponin is a protein found in the heart muscle. When the heart sustains serious damage, these enzymes and proteins leak from the heart muscle cells, indicating a problem. The proteins and enzymes that leak from the heart are transported into the blood stream, so the levels are assessed through a simple blood test.
In addition to heart attacks, infections of the heart muscle can also cause changes in a patient's cardiac enzyme levels. Medications sometimes impact the accuracy of the test, so it is important for patients to provide their physicians with lists of all the medications they take prior to the test.
This simple blood test does not require any special preparation, but it is sometimes necessary to repeat the test. The patient will submit to blood samples several times, with a few hours passing in between tests, to measure changes in cardiac enzyme levels.