Serum Creatinine Phosphokinase (CPK) Activity
This test measures the activity of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain cells. It helps assess damage to these tissues.
["CPK levels can signal muscle, heart, or brain injury."]
Key facts at a glance
- LOINC
- 45135-1
- Short code
- C trach IgG Ser Ql IA
- Synonyms
- C trach IgG 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
- 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
CPK is an enzyme that helps produce energy in cells by breaking down creatine phosphate. When tissues are damaged—such as from a heart attack, muscle injury, or stroke—the enzyme leaks into the bloodstream. This test quantifies how much CPK is present in your serum.
Why It’s Done
Your healthcare provider may order CPK testing to investigate symptoms like muscle weakness, chest pain, or neurological issues. It’s also used to monitor conditions like heart disease, muscle disorders, or to check for complications after trauma or surgery.
Common Uses
CPK is particularly important for diagnosing and managing conditions affecting the heart (e.g., myocardial infarction), skeletal muscles (e.g., rhabdomyolysis), or central nervous system (e.g., stroke). Elevated levels may indicate recent injury or disease progression.
When Results Might Be High or Low
High CPK levels can occur after exercise, muscle injury, or certain medical conditions. Low levels are less common but may suggest severe muscle wasting or rare enzyme deficiencies.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CPK levels often correlate with tissue damage, guiding treatment decisions for conditions like heart attacks, muscle disorders, or neurological events. However, results should be interpreted alongside clinical symptoms and other tests for accurate diagnosis.
Short name
CPK Serum
Frequently asked questions
What causes CPK levels to rise?
How long does it take for CPK levels to return to normal?
Can CPK levels be affected by diet or supplements?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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