Muscle Creatine Phosphokinase (CPK/MB isoenzyme) in Serum or Plasma
This test measures the levels of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain tissues. The MB isoenzyme specifically targets heart muscle damage.
["Helps detect heart muscle injury or strain from conditions like heart attacks or stress."]
Key facts at a glance
- LOINC
- 98687-7
- Short code
- Motor NC Pnl R fibular n
- Synonyms
- Motor NC Pnl R fibular n
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 86430
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is CPK-MB Used For?
CPK-MB is primarily used to identify heart muscle damage. Elevated levels often suggest recent or ongoing heart injury, such as a heart attack (myocardial infarction) or conditions causing stress on the heart, like severe chest pain or high blood pressure episodes.
When Might You Need This Test?
Your doctor may order CPK-MB testing if you’ve experienced chest pain, shortness of breath, or other symptoms that could indicate heart problems. It’s also used in monitoring heart health during procedures or after treatments for heart conditions.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where the CPK-MB isoenzyme is measured using an immunoassay or enzymatic method to detect its presence.
What Are Common Causes of Elevated CPK-MB?
High CPK-MB levels can result from heart attacks, heart surgery, severe chest pain (such as angina), heart valve issues, or conditions causing muscle stress, like extreme exercise or certain medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CPK-MB
Frequently asked questions
Elevated CPK-MB levels are a key indicator of heart muscle damage. While it doesn’t always pinpoint the exact cause, it helps doctors assess heart injury severity and guide treatment decisions, such as medication adjustments or further testing.
Even without obvious symptoms, this test can help detect early signs of heart muscle stress or damage, especially if you’re undergoing medical procedures, have a history of heart issues, or are taking medications that may affect heart function.
CPK-MB levels typically rise within hours after a heart attack or significant heart stress, peaking around 18–24 hours and returning to normal within 3–5 days, depending on the severity of the injury.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy