CPK, MB FRACTION (MASS), SERUM

CPK, MB Fraction (Mass), Serum

What it is

The CPK MB Fraction (Mass), Serum test measures the MB isoenzyme of creatine phosphokinase (CPK) specifically in terms of its mass concentration. CPK-MB is mainly found in the heart muscle, and its measurement is an important tool in evaluating myocardial injury. This test is more specific than total CPK measurement because it isolates the cardiac fraction.

Uses

This test is widely used in the diagnosis of acute myocardial infarction (heart attack) and to assess the extent of cardiac muscle damage. It can also be used to monitor patients with chest pain, evaluate cardiac complications after surgery, and track response to treatment for heart conditions. It is often ordered alongside troponin tests for more accurate diagnosis.

Symptoms That May Lead to the Test

Your doctor may recommend this test if you experience chest pain, shortness of breath, dizziness, excessive sweating, irregular heartbeat, or unexplained fatigue. It is also ordered in patients suspected of having acute coronary syndrome or after cardiac surgery or trauma.

Abnormal Results

Elevated CK-MB Mass: Strongly suggests cardiac muscle injury, most often due to myocardial infarction. It may also be elevated after cardiac surgery, myocarditis, or trauma to the chest.

Normal or Low CK-MB Mass: Usually indicates no significant cardiac muscle damage. However, if measured too early after symptoms start, levels may not yet be elevated, so repeat testing may be needed.

Risks

The test involves a routine blood draw. Risks are minimal and limited to slight pain, bruising, or dizziness at the site of blood collection. These side effects are temporary and uncommon.