Creatine Kinase MB (Blood)Test

What is this test?


This test measures the amount of an isoenzyme of creatine kinase (CK) in your blood. It is called CK-MB.

Your body makes 3 forms of CK, including CK-MB. CK is found in the heart, muscles, and other organs. These include the small intestine, brain, and uterus. If you have a heart attack, injured heart muscle cells release CK-MB into your blood.

Because many tissues contain CK, high levels of CK can be a sign of a variety of problems. Higher CK-MB may point more directly to heart damage.


Why do I need this test?


You may need this test if your healthcare provider thinks you are having a heart attack. Symptoms of a heart attack often include:

  • Pain or discomfort in the chest, such as a squeezing sensation or feeling of fullness

  • Pain in the neck, back, left arm, or jaw

  • Shortness of breath

  • Lightheadedness or dizziness

  • Nausea or vomiting

  • Sudden sweating

  • Tiredness


What do my test results mean?


Test results may vary depending on your age, sex, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you. 

Levels of CK-MB do not rise in your blood within the first 4 to 6 hours after a heart attack. You may need to have repeated tests to see if you’ve had a heart attack.

Higher levels of CK-MB may mean that you have had a heart attack or have other heart problems. These include:

  • Myocarditis. This is an infection and inflammation of the heart muscle.

  • Pericarditis. This is an infection and inflammation of the thin sac that surrounds the heart.

Higher levels of CK-MB may also mean more of the heart was damaged in the attack.

Higher levels may also be caused by muscle damage elsewhere in your body, by diseases that affect your muscles, and trauma to your chest.


How is this test done?


The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand.