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The Test Sample
What is being tested?
This test measures the amount of creatine kinase (CK) in the blood. Creatine kinase is an enzyme found in the heart, brain, skeletal muscle, and other tissues. Increased amounts of CK are released into the blood when there is muscle damage.
The small amount of CK that is normally in the blood comes primarily from skeletal muscles. Any condition that causes muscle damage and/or interferes with muscle energy production or use can cause an increase in CK. For example, inflammation of muscles, called myositis, can increase CK. Rhabdomyolysis, a breakdown of skeletal muscle tissue, is associated with significantly elevated levels of CK.
Rhabdomyolysis and increased CK may be seen with, for example:
- Crush and compression muscle injuries, trauma, burns, and electrocution
- Prolonged surgeries
- Intense physical exertion, especially in heat and humidity and when dehydrated
- Infections – viral (such as influenza and HIV), bacterial, fungal, and parasitic (such as malaria)
- A blood clot (thrombosis) blocking the flow of blood
- Any drug or toxin that interferes with muscle energy production or increases energy requirements
Damage to muscles, such as the heart damage that occurs during a heart attack, can cause increased CK levels within a few hours. Levels peak within 12 to 24 hours and then return to normal within 2 to 4 days. If additional damage occurs or it is ongoing, then CK levels may stay elevated. This fact makes the CK test potentially useful for monitoring for continuing heart or other muscle damage.
How is the sample collected for testing?
A blood sample is taken by needle from the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed.