Welcome to Just Answer and thanks for your question. CPK stands for creatine phosphokinase. It is an enzyme that is found in skeletal muscle tissues, the brain, and the heart. Very high levels of it in a blood test could mean that someone has had heart inflammation, stroke, heart attack or that they have underactive or overactive thyroid or muscle damage (rhabdomyolysis), perhaps from medications like statins for high cholesterol. It is a fairly non-specific test and your doctor will need to determine if the level is significant what it means in your case.