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Serum Creatinine Phosphokinase Isoenzyme Test (CPK-MB)

Published: August 9, 2026Updated: August 16, 2026

This test measures the CPK-MB form of creatine phosphokinase, an enzyme released when heart muscle is damaged. It helps identify heart attack or other cardiac injuries.

Quick summary

["This test helps doctors check for heart muscle damage after injury or stress."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
36932-2
Short code
CT Pit+Sella turc
Synonyms
CT Pit+Sella turc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
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 Does This Test Measure?

CPK-MB is one of three forms of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain cells. When heart tissue is damaged, CPK-MB leaks into the bloodstream. This test specifically looks for the CPK-MB fraction, which is elevated only in heart muscle injury.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like chest pain, shortness of breath, or irregular heartbeat, or if you’ve experienced a heart attack or other cardiac event. It can also be used to monitor heart health in people with known heart conditions.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm or hand to draw blood. If you’re on blood thinners or have a history of bleeding, let your doctor know.

What to Expect During the Test

The test involves a simple blood draw. You may feel a slight pinch, but it usually takes only a few minutes. The blood sample is sent to a lab for analysis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK-MB Isoenzyme

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule. Your doctor will discuss the findings with you.
What are normal results?
Normal results vary by lab and individual. Your doctor will compare your results to your baseline or known health status. Elevated levels may indicate heart damage, but other factors can influence results.
Can I eat or drink before the test?
You can eat and drink normally before the test unless your doctor advises otherwise. Avoid alcohol or heavy meals that day, as they may affect blood chemistry.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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