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Serum Creatinine Phosphokinase (CPK) Activity

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

This test measures the activity level of Creatine Phosphokinase (CPK), 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 in your blood."]

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

Key facts at a glance

LOINC
33331-0
Short code
WNV IgM Titr Ser
Synonyms
WNV IgM Titr 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 CPK Measures

Creatine Phosphokinase (CPK) is an enzyme that plays a role in energy production in cells. When tissues like the heart, skeletal muscles, or brain are damaged, CPK leaks into the bloodstream. This test quantifies how much CPK is present, indicating potential injury.

Why It’s Done

Your doctor may order a CPK test if you have symptoms like chest pain, muscle weakness, confusion, or unexplained fatigue. It’s also used to monitor conditions affecting these organs, such as heart attacks, muscle disorders, or neurological issues.

Common Causes of Abnormal Results

Elevated CPK levels may suggest recent trauma, muscle overuse, heart attack, stroke, or certain metabolic disorders. Low levels could indicate muscle wasting, malnutrition, or rare genetic conditions.

What to Expect Before the Test

No special preparation is needed, but avoid strenuous exercise or consuming large amounts of alcohol 24 hours before testing to get the most accurate results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CPK levels can help diagnose or monitor conditions affecting muscle, heart, or brain function. High levels may signal acute injury, while chronic elevation could indicate ongoing damage or muscle disorders.

Short name

CPK Serum

Frequently asked questions

Why did my doctor order this test?
Your doctor may have suspected muscle, heart, or brain damage based on symptoms like pain, weakness, or other signs. CPK helps confirm or rule out conditions like heart attacks, strokes, or muscle injuries.
Will my results affect my treatment?
If CPK levels are high, your doctor may recommend further tests or treatments to address the underlying cause, such as rest, medication, or lifestyle changes. Follow-up tests may also be needed to monitor recovery.
Can I eat or drink before this test?
You can eat and drink normally unless instructed otherwise. Avoid intense physical activity or heavy alcohol consumption the day before, as these can temporarily alter CPK 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