CK - MB

Creatine Kinase-MB test is used to measure the creatinine kinase-MB levels in the blood. This test is also used to differentiate the damage between the heart muscle and skeletal muscle. This test is also used sometimes to detect a heart attack or to detect a second heart attack or to assess the heart damage.

What is creatine kinase MB?

Creatine kinase-MB is a type of enzyme found mostly in heart muscle cells. Creatinine kinase (CK) enzyme has three forms of isoenzymes. They are- CK-MM, CK-MB, CK-BB. CK-MM is found mostly in heart muscles and skeletal muscles, CK-MB is found mainly in the heart but certain amounts can be found in skeletal muscles, CK-BB is found in the brain and smooth muscles like intestines.

Creatinine kinase is produced from muscle cells and the levels will be raised whenever there is a muscle injury or muscle damage. Certain amounts of CK is always seen in blood in the form of CK-MM. CK-BB is mostly never seen in the blood. Whenever there is a heart damage CK-MB can be observed in the blood. Thus this test is used in detecting a heart problem.

Why is this test performed?

This test is usually recommended when your total CK test levels are too high. This test helps in assessing the reason for elevated levels of total CK in the blood. This test helps to distinguish the damage of heart muscle or skeletal muscle. This is also recommended if you experience chest pain or chest discomfort, pain in the left arm, neck or jaw, shortness of breath, extreme tiredness, dizziness, profuse sweating or nausea, etc. This test results will be at peaks in 12-24 hours after experiencing the symptoms and fall back to normal after 48-72 hours. If there is a second heart attack or the damage is ongoing, then the results will be elevated for a longer duration.

Precautions:

Certain factors may interfere with your test results such as IM injections (intramuscular), recent surgeries, heavy exercise, cardiac catheterization, electromyography (the procedure which is used to test nerve and muscle function). Some medications also cause high levels of CPK in your blood they are, statins, steroids, amphotericin B, anesthetics, etc. Taking alcohol or cocaine before undergoing this test may also disturb your test results.

The reference range may vary depending on the gender, age, health history, your condition, etc.

Since CK-MB test is always done along with total CK test, if the CK-MB and total CK test results are elevated, it may be due to a heart attack. If the levels are dropped and raised later it may indicate a second heart attack. Mostly CK-MB raised levels are observed in the conditions like myocarditis (inflammation or infection of the heart muscle), cardiac defibrillation (electrical shock used to fix rhythm of the heart), pericarditis (inflammation or infection of the pericardium that surrounds the heart.)

If the CK-MB test results and total CK and the CK-MB ratio is more then it may be due to heart damage. The elevated levels of this test may also be due to inflammation, trauma, surgery, ischemia (a condition in which oxygen supply will be decreased) or kidney failure.