Creatine Kinase is an enzyme that is used as part of the energy creation process. Energy in human being is not created by simply burning off carbohydrates, but rather from a more detailed process. At the very core of the process are two chemicals adenosine triphosphate and adenosine diphosphate or ATP and ADP. Energy is created when ATP is converted to ADP, and this is done by enzymes. In certain tissues like the muscles and brain, a store or cache of ATP has to be created and this is where a substance called creatine comes in.
Creatine is a protein that is created in the body itself though it can be acquired by eating meat. Creatine is what breaks ATP into ADP with the resulting extra phosphorus ion binding to creatine to create phosphocreatine. Interestingly, this is a reversible reaction as well, and after the initial burst of energy from ATP to ADP conversion, phosphocreatine can be used to convert ADP to ATP again in under 7 seconds. The enzyme that makes the initial breakdown possible is called creatine kinase.
Creatine kinase comes in two isoforms M and B (muscle and brain). Creatine kinase isoforms in plasma are measured as way of checking for massive muscle damage, heart problems, and acute renal failure. This is because the liver and kidney are the production and processing centers for phosphocreatine and creatine. One of the creatine kinase isoforms in serum is called CKBE. This is an anomaly where creatine kinase is found in the red blood cells. This is a benign condition that occurs in newborns.
The reference ranges of the test for creatine kinase in cardiac tests are: at a lower limit, 24-38-60 and at upper limit 174-320 units per milliliter of blood. The levels vary very slightly between men and women. High levels of creatine kinase in the body are either an indication of renal failure or of massive muscular damage. Since a lot of the enzyme is present in the heat to facilitate a quick release of energy when required, high serum levels indicate that creatine has leaked out from heart tissue, a sign of myocardial infarction. It can also be an indication of muscle injury, muscle breakdown, muscular dystrophy, or inflammation. Sometimes a specific test is made for creatine kinase MB. Another enzyme that is specifically tested in cardiac tests is troponin. This is tested because it is usually only found in the muscles of the heart.