Creatine phosphokinase (CPK) is an enzyme found in the heart, brain, and skeletal muscle. Muscle cells make this enzyme in order to function, when muscle cells are injured or unhealthy, these enzymes leak out of muscle cells and into the blood stream. Myositis damages muscle tissue, so in many cases raised CPK levels aid in the diagnosis of myositis.
CPK levels above 200 units per liter can indicate muscle disease. In some patients however, CPK levels do not rise, especially after prednisone use, therefore CPK levels are not always indicative of active disease.
Through our support groups we have learned some patients will never experience a rise in their CPK level yet have active Myositis. This becomes a good tool once a baseline is established for doctors to monitor from that point.Tags: myositis testing