Blood-tests Explained


Disclaimer:

This website is intended to assist with patient education and should not be used as a diagnostic, treatment or prescription service, forum or platform. Always consult your own healthcare practitioner for a more personalised and detailed opinion

CK-MB


At a Glance

Why Get Tested?

To distinguish between skeletal muscle and heart muscle damage; sometimes to determine if you have had a heart attack (if the troponin test is not available); sometimes to detect a second or subsequent heart attack or to monitor for additional heart damage

When to Get Tested?

When you have an increased creatine kinase (CK) level and the healthcare practitioner wants to determine whether it is due to skeletal or heart muscle damage; when it is suspected that you have had a second heart attack or have ongoing heart damage

Sample Required?

A blood sample drawn from a vein in your arm

Test Preparation Needed?

None

The Test Sample

What is being tested?

Creatine kinase-MB (CK-MB) is a form of an enzyme found primarily in heart muscle cells. This test measures CK-MB in the blood.

CK-MB is one of three forms (isoenzymes) of the enzyme creatine kinase (CK). These isoenzymes include:

  • CK-MM (found in skeletal muscles and the heart)
  • CK-MB (found mostly in the heart, but small amounts found in skeletal muscles)
  • CK-BB (found mostly in the brain and smooth muscle, such as the intestines and uterus)

CK is released from muscle cells and is detectable in the blood whenever there is muscle damage. The small amount of CK that is normally in the blood is primarily CK-MM. CK-BB almost never gets into the blood, and CK-MB will typically only be present in significant amounts when the heart is damaged. A CK test measures the total level but does not distinguish between the three isoenzymes. When there is an increased amount of CK present in the blood, the CK-MB test can be used to determine whether it is due to heart damage or is more likely to be related to skeletal muscle injury.

How is the sample collected for testing?

A blood sample is taken by needle from a vein in the arm.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is usually needed because the test is done in emergency care.

The Test