CK-MB, Creatine Kinase-MB

This is a test of an enzyme level. CK-MB is one of three separate forms of the enzyme creatine kinase (CK). CK-MB is found mostly in heart muscle. It rises when there is damage to heart muscle cells.

CK-MB levels, along with total CK, are tested in persons who have chest pain to diagnose whether they have had a heart attack. Since a high total CK could indicate damage to either the heart or other muscles, CK-MB helps to distinguish between these two sources. If your doctor thinks you have had a heart attack and gives you a "clot-dissolving" drug, CK-MB can help your doctor tell if the drug worked. When the clot dissolves, CK–MB tends to rise and fall faster. By measuring CK-MB in blood several times, your caregiver can usually tell whether the drug has been effective.

CK-MB is usually ordered, along with total CK, in persons with chest pain to determine whether the pain is due to a heart attack. It may also be ordered in a person with a high CK to determine whether damage is to the heart or other muscles.

PREPARATION FOR TEST

A blood sample drawn from a vein in the arm

NORMAL FINDINGS

Total CK

  • Adult/elderly (Values are higher after exercise.)

  • Male: 55-170 units/L or 55-170 units/L (SI units)

  • Female: 30-135 units/L or 30-135 units/L (SI units)

  • Newborn: 68-580 units/L (SI units)

Isoenzymes

  • CK-MM: 100%

  • CK-MB: 0%

  • CK-BB: 0%

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your doctor after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.

MEANING OF TEST

Your caregiver will go over the test results with you and discuss the importance and meaning of your results, as well as treatment options and the need for additional tests if necessary.

OBTAINING THE TEST RESULTS

It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.