No longer in routine clinical use
A blood sample taken from a vein in the arm
Creatine kinase (CK) is an enzyme that occurs in three major forms, called isoenzymes:
- CK-MB (found mostly in heart muscle)
- CK-BB (found mostly in brain)
- CK-MM (found in muscles)
CK–MB rises when there is any damage to heart muscle cells. Total CK is routinely available in most laboratories and used to indicate muscle disease.
How is the sample collected for testing?
A blood sample is taken by needle from the arm.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is required.
How is it used?
CK-MB was once the primary test requested for people who had persistent chest pain to see if the pain was coming from the heart. It has now been replaced by the troponin test, which is more specific and sensitive.
When is it requested?
It is no longer in routine use within the UK. It may rarely be requested if a total CK concentration is raised but no clear source is identified.
What does the test result mean?
Increased CK-MB concentrations can usually be detected in someone with a heart attack about 4-6 hours after the onset of chest pain. The level of CK-MB peaks approximately at 12-24 hours after the onset of chest pain and then returns to normal within about 48-72 hours.
Is there anything else I should know?
CK-MB levels may be increased by extensive trauma to skeletal muscles.