Serum Creatine Kinase, Isoenzyme MB (CK-MB)

Why Is This Test Done?

Your doctor may order a CK-MB test if you have symptoms like chest pain, shortness of breath, or unexplained fatigue. It’s also used after a heart attack to monitor recovery or check for complications. Sometimes, it’s part of a broader heart health evaluation, especially if you have risk factors like high blood pressure or a family history of heart disease.

What Does a High or Low Result Mean?

Elevated CK-MB levels often signal recent or ongoing heart muscle damage, such as a heart attack. Very low levels may indicate normal heart function or, rarely, certain medical conditions affecting muscle or nerve health. Your doctor will interpret results in the context of your symptoms and other tests.

How Is This Test Performed?

A blood sample is taken from a vein, usually in your arm. The blood is sent to a lab where it’s analyzed to measure CK-MB levels using an immunoassay method, which detects the enzyme’s presence with high sensitivity.

What Can Affect Results?

Factors like recent exercise, muscle injuries, or certain medications (e.g., statins) can temporarily raise CK-MB levels. Infections, dehydration, or other illnesses may also influence results. Always inform your doctor about all medications or conditions before testing.