Serum Creatinine Phosphokinase (CPK) or Creatine Kinase (CK) Activity
This test measures the activity of creatine kinase, an enzyme found in heart, muscle, and brain cells. It helps assess damage to these tissues.
["CPK/CK helps identify muscle or heart injury by detecting elevated enzyme levels in the blood."]
Key facts at a glance
- LOINC
- 111310-9
- Short code
- C trach IgM Msmt Ser
- Synonyms
- C trach IgM 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/CK Used For?
CPK/CK is primarily used to diagnose and monitor conditions affecting muscle or heart tissue, such as heart attacks, muscle injuries (e.g., from overexertion or trauma), or certain neurological disorders. It can also help determine the severity of these conditions by measuring how much enzyme leaks into the bloodstream after damage occurs.
Why Might You Need This Test?
Your healthcare provider may order CPK/CK if you have symptoms like chest pain, muscle weakness, confusion, or unexplained fatigue. It’s also used in follow-ups for patients with known heart disease, recent injuries, or conditions like myopathy (muscle disorders).
How Is the Test Performed?
A blood sample is taken from a vein in your arm. The sample is sent to a lab, where the enzyme activity is measured using a specialized test. The result tells your doctor how much CPK/CK is present, indicating tissue damage if levels are elevated.
What Do the Results Mean?
Elevated CPK/CK levels suggest recent muscle or heart injury. However, results alone don’t diagnose a condition—they’re used alongside other tests and symptoms. Normal levels don’t rule out injury if you have symptoms. Your doctor will interpret results in the context of your medical history and other findings.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CPK/CK Activity
Frequently asked questions
What causes high CPK/CK levels?
Low CPK/CK levels are less common but may occur in people with severe muscle wasting (e.g., from long-term illness), certain genetic disorders, or rare metabolic conditions. They’re usually not a cause for concern unless accompanied by other symptoms.
Your doctor will determine how often you need CPK/CK testing based on your health status. For example, heart patients may get it regularly, while others might only need it if they experience symptoms or undergo procedures that could damage muscle or heart tissue.
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