Creatine Kinase
Reviewed
Also called: CK test, total CK, creatine phosphokinase, CPK
This test measures the amount of creatine kinase (CK) in a sample of your blood. CK is an enzyme that helps make energy. Most of the CK in your body is in your skeletal muscles. Normally, a small amount of CK gets into your blood from the usual wear and tear on your muscles. But if your muscles, heart, or brain tissues are damaged, larger amounts of CK leak out of your cells into your bloodstream. A CK test is mainly used to help diagnose and monitor injuries and diseases that damage skeletal muscles and cause high levels of CK in your blood.
Specimen: blood
Why this test may be ordered
- To help diagnose and monitor muscle injuries, including injuries from accidents, serious burns, or extreme exercise.
- To help diagnose and monitor muscle diseases, including muscular dystrophy, rhabdomyolysis, and myositis.
- In certain cases, to help diagnose a heart attack (though a troponin test is used more often).
- If you have had a stroke, to find out how severe it was and help predict the chance of another stroke.
- If you have had an injury that crushed or tore your muscles, have had serious burns, take certain medicines that may cause muscle damage (such as statins), or have had a stroke or traumatic brain injury.
Preparation and collection
You do not need any special preparations. To help make sure your results are accurate, your provider may ask you to avoid intense exercise and drinking alcohol for a few days before your test.
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. This usually takes less than five minutes.
There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.
Understanding results
Normal CK levels depend on your age, sex, race, how much muscle you have, and how physically active you are. If your CK level is higher than normal, it usually means you have some type of muscle damage. But a CK test result cannot show where the damage is or what is causing it.
- Higher than normal CK level: Your CK level is higher than normal. This usually means you have some type of muscle damage. CK levels that stay high or increase may mean that muscle damage is continuing to happen. Limitation: A CK test result cannot show where the damage is or what is causing it. Next step: Your provider will consider your symptoms and medical history to understand what your test results mean. If the source of high or increasing CK levels is not clear, you may need a more specific type of CK test called a CK isoenzymes test.
- Normal CK level: Your CK level is normal. This means there is no significant muscle damage detected at this time. Limitation: A CK test result cannot show where the damage is or what is causing it. Next step: Your provider will consider your symptoms and medical history to understand what your test results mean.
- A CK test result cannot show where the damage is or what is causing it.
- CK levels may not reach their highest until up to two days after certain injuries, so you may need more than one test to see if your levels go up or down.
- To diagnose the condition causing high CK levels, you may need other types of tests.
What to do next
Your provider will consider your symptoms and medical history to understand what your test results mean. If the source of high or increasing CK levels is not clear, you may need a more specific type of CK test called a CK isoenzymes test to find out if the CK is coming from your muscles, heart, or brain. To diagnose the condition causing high CK levels, you may need other types of tests, too. The tests you have will depend on which types of CK enzymes are high as well as your symptoms and medical history.
- What do my CK test results mean in relation to my symptoms and medical history?
- Do I need a CK isoenzymes test or other follow-up tests?
- What is the likely cause of any muscle damage indicated by my results?