Serum Creatinine Kinase (CK) Activity
This test measures the activity of an enzyme called creatinine kinase, which helps assess muscle health and detect conditions affecting your muscles or heart.
["CK helps identify muscle damage or heart-related issues by measuring enzyme levels in your blood."]
Key facts at a glance
- LOINC
- 48461-8
- Short code
- MR Neck Ltd
- Synonyms
- MR Neck Ltd
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 22
- Ref high
- 198
- Critical range
- — – 10000 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- mr
- CPT
- 82553
- 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 Creatinine Kinase (CK) Used For?
CK levels can help diagnose muscle injuries, such as from overexertion or trauma, or conditions like myopathies (muscle diseases). It may also be checked after a heart attack to monitor heart muscle damage or assess recovery. Doctors sometimes use CK alongside other tests to evaluate conditions like rhabdomyolysis (severe muscle breakdown).
Why Might Your Doctor Order This Test?
Your doctor may order CK testing if you’ve experienced unexplained muscle weakness, pain, or tenderness, or if you’ve had recent trauma, surgery, or a heart-related event. It’s also part of some routine health checks, especially in athletes or older adults.
What to Expect Before or After the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood. If you’re concerned about pain, let your healthcare provider know. After the test, you’ll likely feel minimal discomfort, and you can resume normal activities immediately.
Possible Results and Next Steps
Results may be compared to your baseline or reference ranges to identify abnormal levels. High CK could signal muscle damage, while very low levels might raise questions about underlying conditions. Your doctor will discuss results with you and recommend next steps, such as further testing or lifestyle adjustments.
Reference range
Adult males: 22-198 U/L; Females: 22-198 U/LN/A
No special preparation required. Inform provider of any chest pain or symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CK Serum
Frequently asked questions
How often is CK tested in routine health checks?
CK levels can rise due to muscle damage from exercise, injuries, or conditions like myositis (inflammation of muscles). It may also be elevated after heart attacks, strokes, or certain infections. Stress, certain medications, or metabolic disorders can sometimes contribute.
Dietary changes alone rarely affect CK levels, but some supplements (like creatine or certain vitamins) may interact with muscle health indirectly. If you’re taking supplements, discuss them with your doctor to ensure they don’t interfere with test results or your treatment plan.
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 17, 2026. · Read our editorial policy