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Serum Creatinine Phosphokinase (CPK) Activity

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

This test measures the activity of an enzyme called Creatine Phosphokinase (CPK), which helps assess muscle, heart, and brain health. CPK levels can rise if tissues are damaged.

Quick summary

["CPK helps detect muscle or heart damage by measuring enzyme levels in your blood."]

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

Key facts at a glance

LOINC
31510-1
Short code
M cap caprip Ab Ser Ql
Synonyms
M cap caprip Ab Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Creatine Phosphokinase (CPK)?

Creatine phosphokinase (CPK), also called creatine kinase (CK), is an enzyme found in heart, muscle, and brain cells. When these tissues are damaged—due to injury, illness, or overuse—the enzyme leaks into the bloodstream, raising CPK levels. This test helps doctors identify conditions like heart attacks, muscle injuries, or neurological issues.

Why Might You Need This Test?

Your doctor may order CPK testing if you have symptoms like chest pain, muscle weakness, confusion, or unexplained fatigue. It’s also used after trauma, surgery, or during monitoring for conditions like myopathy (muscle disorders) or heart disease.

Common Causes of Elevated CPK Levels

High CPK levels can result from muscle injuries (e.g., strains, cramps), heart attacks, stroke, or certain medications. Low levels are less common but may occur with severe muscle wasting or certain genetic 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 that affect muscle function, let your doctor know.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK Serum

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on lab processing. Follow-up with your doctor to discuss findings.
Can CPK levels be affected by diet?
Diet alone rarely changes CPK levels, but high-protein or intense exercise may temporarily raise them. Avoiding strenuous activity before testing helps get more accurate results.
Is CPK testing painful?
No, this test involves a simple blood draw, similar to other routine lab tests. Most people experience only mild discomfort or a brief pinch at the injection site.
  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