A CPK test might be ordered by your doctor to check for muscle related diseases or problems, as well as in the emergency room if a heart attack is suspected.
CPK stands for creatine phosphokinase, and it is an enzyme that helps turn creatine into phosphate which is burned for energy. CPK leaks out of muscles into the bloodstream when there is damage to the heart muscle or other muscles in your body. As such it is a good indication that something is wrong and needs to be addressed.
What is the CPK Blood Test All About?
The CPK enzyme, also called creatine kinase (CK), is found throughout your body, mostly in your skeletal muscle as well as your brain and your heart. The CPK blood test is like any other, with the technician drawing blood through a needle into vials which are then analyzed.
Based on the type and levels of the enzyme in your blood, doctors can determine which muscles specifically are affected as well as the extent of the damage. There will likely be other tests performed simultaneously for a more accurate diagnosis.
If you have chest pain and/or a heart attack, or have issues with other muscles in your body, the test should help pinpoint the problem. There are three different types of CPK, making it easier to locate the issue.
If levels of CPK-1 are found to be out of range, that means the problem lies in the brain or the lungs. If it’s CPK-2, there is an issue with the heart, and if it’s CPK-3, it’s the skeletal muscle.
What Does it Mean When Your CPK is High?
The CPK test normal range is between 10 and 120 mcg/L, or micrograms per liter. These results can vary from one lab to the next, as is the case for most blood tests.
High CPK levels, meaning over 120 mcg/L, could be a sign of a heart attack, stroke, inflammation of the heart, myopathy (muscle disease), lung tissue disease, muscular dystrophy, or serious muscle breakdown called rhabdomyolysis, one of the more serious side effects of statin drugs.
If your CPK-1 levels are high, it is likely a brain injury or cancer, a seizure or pulmonary infarction, which is long tissue death from lack of blood supply.
If your CPK-2 levels are high, it can be a sign of a heart attack. Typically the levels will rise a few hours after you have a heart attack and return to normal levels with 48 hours if there isn’t additional muscle damage.
Other heart related issues that can cause a higher CPK test result are myocarditis (inflammation), injury, surgery and defibrillation.
Lastly, if CPK-3 concentration is above normal, it can be a sign of general muscle issues such as muscle breakdown, inflammation, sugeries, medical tests or even very strenuous exercise.
What Does it Mean When Your CPK is Low?
Although most of the focus is on higher CPK blood test results, low CPK levels can also be a sign of a health issue. In the case of alcohol induced liver disease, rheumatoid arthritis (RA), connective tissue diseases, Cushing’s disease and acute viral hepatitis, creatine phosphokinase levels may be lower than normal.
However, the CPK blood test is usually performed to detect higher levels to localize muscle damage. A lower than normal reading is rare and if found is not a definitive indication of a particular problem. It can be helpful in that it will encourage more precise testing to rule out or confirm a diagnosis of the particular health condition.
What is the Treatment For Elevated CPK Levels?
The treatment for an abnormal CPK result will depend on what the determination is. Since high CPK levels can be temporary and due to a surgery, injection, medication or exercise, for example, doctors will often recheck a short time later to see if they get the same result or if levels have returned to within normal range.
If a more serious problem such as a heart attack or a stroke is suspected, and CPK levels are high, doctors will typically order other blood tests to confirm their diagnosis.
One such test is the troponin test, which measures the amount of troponin T and I proteins in the blood. Similar to the CPK enzyme, when there is heart muscle damage the levels of troponin will increase. The more damage, the higher the number.
There is also the serum myoglobin test, another heart protein that will leak into the blood stream if there is any damage to the heart muscle. Again, the more myoglobin found in your blood, the more damage has likely occurred in the heart.
Of course, these three blood tests are not the only procedures performed. An EKG will be done to determine the extent of the damage, an echocardiography will see how the heart is pumping, and other tests will be done to get a full picture of the state of your heart and cardiovascular system.
So the treatment for CPK obviously depends on what caused it to go up. In some cases no treatment will be necessary. In others some medical intervention might be necessary.