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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 helps identify muscle, heart, or brain injury by detecting elevated enzyme levels."]

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

Key facts at a glance

LOINC
109377-2
Short code
EBV VCA IgA Msmt Ser
Synonyms
EBV VCA IgA Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 CPK Used For?

CPK levels are often checked after trauma, heart attacks, or muscle injuries to monitor for tissue damage. High levels may signal conditions like heart attacks, muscle strains, or neurological issues.

Why Might You Need This Test?

Your doctor may order CPK if you’ve experienced chest pain, muscle weakness, or symptoms like confusion, which could indicate organ stress. It’s also used in diagnosing conditions like myositis or rhabdomyolysis.

What to Expect Before the Test

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

What to Expect During the Test

A small blood sample is drawn from a vein, usually in your arm. It’s quick and rarely causes discomfort. The sample is sent to a lab for enzyme activity measurement.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

CPK (Serum/Plasma)

Frequently asked questions

How high or low are my CPK levels?
CPK levels vary by age, sex, and health. High levels (above normal) may indicate muscle damage, heart issues, or other conditions. Low levels are less common but could signal muscle wasting or certain metabolic disorders. Always discuss results with your doctor.
Could my diet or exercise affect CPK?
Moderate exercise usually doesn’t raise CPK levels significantly. However, intense or prolonged exercise may temporarily increase it. Avoid overexertion before testing to get accurate results.
What if my CPK is elevated?
If elevated, your doctor may investigate further to rule out muscle injury, heart problems, or other conditions. Follow-up tests or treatments may be recommended based on your symptoms and 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