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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 by detecting damage or stress.

Quick summary

["CPK helps identify potential muscle or heart injury by measuring enzyme release into your blood."]

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

Key facts at a glance

LOINC
37633-5
Short code
XR Pelvis 1V W Stand
Synonyms
XR Pelvis 1V W Stand
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
xr
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, is an enzyme found in high concentrations in heart, skeletal muscle, and brain tissues. When cells are damaged—such as from a heart attack, muscle injury, or stroke—the enzyme leaks into the bloodstream, raising its levels. This test helps doctors evaluate conditions affecting these organs.

Why Might You Need This Test?

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

Common Conditions Monitored

Elevated CPK levels may signal muscle damage (e.g., from overexertion, injury, or myopathies), heart problems (e.g., myocardial infarction), or neurological disorders (e.g., stroke). Low levels may indicate muscle wasting or certain metabolic disorders.

What to Expect Before the Test

No special preparation is needed, but avoid strenuous exercise 24 hours before testing. If you’re on medications (e.g., statins, steroids), let your doctor know—some can affect CPK levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK (Serum)

Frequently asked questions

Could my CPK levels be affected by my diet?
Diet alone rarely affects CPK levels, but certain foods (e.g., high-fat meals) or supplements (e.g., creatine) may influence muscle enzyme release indirectly. Focus on hydration and balanced nutrition to support overall health.
What if my CPK is high?
High CPK may require further testing (e.g., troponin for heart issues) or evaluation of triggers like recent illness, trauma, or medications. Your doctor will discuss next steps based on your symptoms and medical history.
How often should I get this test?
Frequency depends on your health status. If you have a known condition (e.g., heart disease), your doctor may schedule regular checks. Otherwise, this test is usually ordered as needed for symptoms or monitoring.
  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