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Creatine kinase, CK for short, is an enzyme found mainly in your muscles that helps make energy. A high level in your blood can point to damage to your muscles, your heart or your brain.[1]
On this page you can read what creatine kinase is, what the guidelines say about a level that is too low or too high, what affects your level and which other markers are best read alongside it.
Also known as: total CK, creatine phosphokinase, CPK. At the lab: CK.
CK is an enzyme. An enzyme is a protein that makes certain chemical reactions in your body happen faster. CK helps make energy. It is also called creatine phosphokinase, or CPK.[1]
Most CK is found in your skeletal muscles. These are the muscles you move with. There is also CK in your heart muscle, and a small amount in your brain.[1]
There are three types of CK. A high level of CK-MM is usually caused by damage to the skeletal muscles. A high level of CK-MB is usually caused by damage to the heart muscle. A higher level of CK-BB can point to damage to the brain, or to a disorder of the smooth muscles, such as those of your digestive system.[1]
Normally only a small amount of CK gets into your blood. If your muscles, your heart or your brain tissue are damaged, more CK leaks out of your cells into your blood.[1]
That is why the test is mainly used to detect and monitor damage to the skeletal muscles. Think of damage from an accident, severe burns or extreme exertion. A doctor may also look at CK in inherited muscle disorders, a rapid breakdown of muscle tissue or long-term inflammation of the muscles.[1]
A doctor sometimes also looks at CK when there is damage to the heart muscle. A different blood test, troponin, is more often used for this, because it is better at finding heart muscle damage. After a sudden brain condition, CK can help estimate how serious it was.[1]
A doctor may order the test if you have muscle symptoms. For example, muscle pain or cramps, weak muscles, problems with your balance or falling often, numbness or tingling, dark urine or swollen legs or feet.[1]
Labplusarts, the lab BioProfile works with, uses a reference value of 0 to 170 u/l for creatine kinase (CK). The lab calls a level between these limits normal.[2]
| Value | What it can mean | Who it is for |
|---|---|---|
| 0 to 170 u/l[2] | The lab calls this value normal | The lab does not name a separate group |
Source: Labplusarts, reference value for creatine kinase (CK), list of 24 September 2026. The source gives one range and no separate values per group.[2]
A higher than normal level can point to some form of muscle damage. After some types of damage, CK does not peak until up to two days later. That is why more than one test sometimes follows, to see whether your level is rising or falling. If your level stays high or rises, this can be a sign that the damage is ongoing. The test does not show where the damage is or what caused it. If that is unclear, a test of the three types of CK can tell you more.[1]
BioProfile is working on its own zones for each value, from risk to optimal. A doctor reviews those zones before they appear in your result.
Hard exercise shortly before the test can raise your CK. That is why your doctor may ask you not to do any hard exercise or drink alcohol for a few days before the test. This makes your result as reliable as possible.[1]
Some medicines can cause muscle damage and so raise your CK. One example is statins, which lower the cholesterol in your blood.[1]
What counts as a normal level for you depends on your age, your sex and your ethnic background. How much muscle you have and how active you are also play a part.[1]
A rapid breakdown of muscle tissue can be caused by, among other things, working in very hot places or overloading your muscles. This releases CK into your blood.[1]
Creatine kinase is included in BioProfile 87, 121 and 150.[3]
The BioProfile editorial team wrote this page on 10 October 2026 from the sources below, which we read on 10 October 2026. Every number on this page appears in one of those sources, with that source's number next to it. An expert has yet to check this page; after that check, the expert's name and the date of the check will appear at the top. This page offers explanation, not a diagnosis. Discuss a value outside the range with your GP.
