Skip to content

Serum Creatinine Phosphokinase Isoenzyme MB (CPK-MB)

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

This test measures a specific form of the enzyme creatine phosphokinase (CPK), which is found mostly in heart muscle. It helps assess damage to the heart tissue.

Quick summary

["This test can help identify heart muscle injury or stress."]

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

Key facts at a glance

LOINC
15049-0
Short code
CK MM CFr SerPl Elph
Synonyms
CK MM CFr SerPl Elph
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
7.2 N/A – 7.6 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
electrophoresis
CPT
82553
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

Why This Test Is Done

Your healthcare provider may order a CPK-MB test if you have symptoms like chest pain, shortness of breath, or irregular heartbeat. It may also be used after a heart attack to monitor recovery or in cases of suspected heart injury from conditions like a heart attack, heart surgery, or severe chest trauma.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into a vein in your arm to draw blood. This is usually done in a clinic or lab.

What the Test Results Mean

Elevated levels of CPK-MB can indicate heart muscle damage. However, results alone do not diagnose a heart condition. Your doctor will review the results with other tests and symptoms.

Common Causes of Abnormal Results

High CPK-MB levels can be caused by heart attacks, heart surgery, severe heart stress, or other conditions affecting heart muscle. Other conditions, like muscle injuries or certain diseases, can also raise CPK-MB levels.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK-MB Isoenzyme

Frequently asked questions

What happens if my CPK-MB test results are abnormal?
If your results are elevated, your doctor may order additional tests to determine the cause. This could include more heart-related tests, imaging studies, or further blood tests to monitor your heart health. Follow-up may involve lifestyle changes, medications, or other treatments based on your diagnosis.
Can CPK-MB levels return to normal after a heart attack?
Yes, CPK-MB levels typically return to normal within a few days to weeks after a heart attack, depending on the severity of the damage. Your doctor will monitor your levels and overall health to ensure proper recovery.
Does diet or exercise affect CPK-MB levels?
While diet and exercise do not directly affect CPK-MB levels, they can influence overall heart health. Engaging in regular physical activity and maintaining a healthy diet can support heart function and may indirectly help manage conditions that could affect CPK-MB levels.
  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