Serum Creatinine Phosphokinase (CPK) Isoenzyme Assay (Total CPK)
This test measures the total level of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain tissues. It helps assess damage to these areas, often due to injury, illness, or other conditions.
["CPK levels can indicate muscle or heart damage; elevated results may signal injury or disease needing medical attention."]
Key facts at a glance
- LOINC
- 20720-9
- Short code
- BRUCABRT
- Synonyms
- B abortus Ab Mlk Ql Ser ring aggl
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof plastic or glass container suitable for milk collection (e.g., 50 mL screw-cap vial); avoid preservatives
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- aggl-serial-ring-test
- SNOMED
- 16554009
- Specimen volume
- 10-50 mL of fresh whole milk
- Stability
- Refrigerated (2-8°C): up to 48 hours. Do not freeze. Test promptly after collection for optimal results.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 2–24 hours
- Order
- routine
What Is Creatine Phosphokinase (CPK)?
Creatine phosphokinase (CPK), also called creatine kinase (CK), is an enzyme that helps produce energy in cells. It exists in three main forms (isoenzymes) in the body: brain (CPK-B), heart (CPK-MB), and muscle (CPK-MM). This test measures the total CPK activity in your blood, combining all three forms. CPK is released into the bloodstream when tissues are damaged, making it useful for diagnosing conditions like heart attacks, muscle injuries, or neurological issues.
Why Might This Test Be Ordered?
Your doctor may order this test if you have symptoms like muscle pain, weakness, chest pain, or shortness of breath. It can also be used to monitor conditions such as heart disease, muscle disorders, or stroke. Elevated CPK levels may suggest recent trauma, inflammation, or metabolic disorders.
What to Expect Before the Test
No special preparation is needed for this blood test. You may be asked to fast for a few hours before the draw, but this depends on your doctor’s instructions. Wear a loose shirt and avoid strenuous activity on the day of the test.
What Happens During the Test
A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the process is quick. The blood sample is then sent to a lab for analysis using an immunoassay or enzymatic method to measure CPK activity.
Reference range
Negative: No ring formation at the cream layer with homogeneous blue/blue-purple coloration of milk. Positive: Blue ring at the cream layer with clearing of underlying milk. Reactions may be reported as +, ++, +++, or ++++ based on ring intensity.N/A
Not applicable for milk samples (animal specimen). Milk sample should be collected from individual animals or bulk tank. Use fresh, non-homogenized, non-bacterially contaminated milk. Samples should not be frozen or subjected to excessive heat prior to testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CPK levels can signal muscle damage (myopathy), heart muscle strain (such as during a heart attack), or neurological conditions. However, CPK alone may not always indicate the exact cause. Your doctor will review results alongside other symptoms, medical history, and tests to provide a diagnosis. Normal or slightly elevated levels may not require immediate action, but persistent or high results warrant further evaluation.
Short name
Total Creatine Phosphokinase (CPK) Serum
Frequently asked questions
What causes CPK levels to rise?
How long does it take to get results?
Can CPK levels be affected by diet or exercise?
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