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Serum or Plasma Creatinine Phosphokinase (CPK) Activity

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

This test measures the activity of creatine phosphokinase, an enzyme found in heart, muscle, and brain tissues. It helps assess damage to these organs.

Quick summary

["CPK levels can signal muscle, heart, or brain injury."]

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

Key facts at a glance

LOINC
15487-2
Short code
M meleagridis Ab Ser Ql IA
Synonyms
M meleagridis Ab Ser Ql IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 CPK Does in Your Body

Creatine phosphokinase (CPK) is an enzyme that helps produce energy in cells. When tissues—such as heart muscle, skeletal muscle, or brain—are injured, CPK leaks into the bloodstream. This test measures how much CPK is present, indicating potential damage.

Common Causes of Elevated CPK

High CPK levels may occur after muscle injury (e.g., from exercise, trauma, or overexertion), heart problems (such as a heart attack), or neurological conditions. Rarely, it can be linked to certain infections or metabolic disorders.

When This Test Might Be Ordered

Your doctor may request CPK testing if you have symptoms like muscle pain, weakness, chest pain, or neurological issues. It’s also used to monitor conditions like heart disease or muscle disorders.

What to Expect Before the Test

No special preparation is needed, but avoid intense exercise 24 hours before testing. If you’re on medications, let your doctor know—some may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CPK levels often point to tissue damage, guiding treatment for conditions like heart attacks, muscle injuries, or neurological events. Low levels may require further investigation to rule out deficiencies or hidden health risks.

Short name

CPK (Serum/Plasma)

Frequently asked questions

Why might my CPK test be ordered if I don’t have symptoms?
Your doctor may order CPK testing as part of a routine checkup, to monitor a known condition (e.g., heart disease, muscle disorders), or to investigate unexplained symptoms like fatigue or muscle weakness.
Can CPK levels change based on diet or exercise?
Yes, intense exercise can temporarily raise CPK levels due to muscle damage. Avoid strenuous activity 24 hours before testing to get a more accurate result.
What if my CPK is very high? What does that mean?
Very high CPK may signal severe tissue damage, such as a heart attack, muscle rupture, or neurological injury. Your doctor will discuss next steps based on your symptoms and test results.
  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