Serum Creatinine Phosphokinase (CPK) Isoenzyme Assay (Total CPK)
This test measures the total activity of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain tissues. It helps assess muscle damage or heart-related conditions.
["CPK levels can signal muscle or heart injury; elevated results may indicate damage to these tissues."]
Key facts at a glance
- LOINC
- 33078-7
- Short code
- GA from AXT.Shinozuka96
- Synonyms
- GA from AXT.Shinozuka96
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0.4
- Ref high
- 4
- Critical range
- 0.1 N/A – 20 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-estimated-from-axt-shinozuka
- CPT
- 84443
- SNOMED
- 301343003
- 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
Why This Test Might Be Ordered
Your doctor may recommend this test if you have symptoms like muscle weakness, pain, or shortness of breath, or if you’re experiencing unexplained fatigue. It’s also used to monitor conditions such as heart attacks, muscle disorders, or nerve damage.
What to Expect Before the Test
No special preparation is needed, but avoid heavy exercise or strenuous activity 24 hours before testing. If you’re on medications, let your doctor know—some may affect results.
What the Results Mean
CPK levels can vary based on factors like age, sex, and overall health. High levels may suggest muscle or heart damage, while low levels could indicate muscle wasting or certain metabolic conditions.
Common Causes of Abnormal Results
Elevated CPK is often linked to muscle injuries (e.g., from exercise, trauma), heart attacks, or conditions like myositis. Low CPK might be due to muscle atrophy, liver disease, or rare genetic disorders.
Reference range
Adult: 0.4-4.0 mIU/LN/A
Take your thyroid medication after the blood draw if applicable. No fasting required.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical significance: Elevated CPK is a marker for tissue injury, particularly in muscles or the heart. It’s often used alongside other tests (like troponin for heart damage) to diagnose conditions like myocardial infarction, rhabdomyolysis, or severe muscle trauma. Low CPK may warrant further investigation for underlying metabolic or neuromuscular disorders.
Short name
Total CPK (Serum)
Frequently asked questions
What triggers CPK elevation?
How long does it take to get results?
Can diet or supplements affect CPK levels?
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