Serum Creatinine Phosphokinase (CPK) Isoenzyme Activity
This test measures the activity of a specific form of the enzyme Creatinine Phosphokinase (CPK), which is found in heart, muscle, and brain tissues. It helps assess damage to heart muscle after a heart attack or other cardiac events.
["This test helps doctors check for heart muscle injury or strain."]
Key facts at a glance
- LOINC
- 35301-1
- Short code
- CDT-ASIALO-CSF
- Synonyms
- CDT Asialo CSF Ql
- Category
- chemistry
- Sample
- csf
- Container
- Sterile CSF collection tubes (polypropylene), preferably screw-cap cryovials for transport
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Isoelectric focusing (IEF) with immunoblotting or high-performance liquid chromatography (HPLC)
- CPT
- 82373
- SNOMED
- 395148009
- Specimen volume
- 0.5 to 1.0 mL of cerebrospinal fluid
- Stability
- Refrigerated (2-8°C): up to 7 days; Frozen (-20°C or below): up to 4 weeks; Avoid repeated freeze-thaw cycles
- Hemolysis max
- 200
- TAT
- 48–168 hours
- Order
- routine
What Does This Test Measure?
Creatinine Phosphokinase (CPK) is an enzyme that helps convert phosphocreatine to creatinine and ATP (energy) in cells. The CPK-MB isoenzyme is particularly concentrated in heart muscle cells. Elevated levels in the blood can indicate recent heart damage, such as a heart attack.
Why Might You Need This Test?
Your doctor may order this test if you’ve experienced symptoms like chest pain, shortness of breath, or unusual fatigue, or if you’ve had a suspected heart attack or other cardiac event. It’s also used in monitoring heart health during conditions like heart failure or after heart surgery.
How Is This Test Performed?
A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where the CPK-MB activity is measured using an immunoassay method, which detects the enzyme’s presence and activity.
What Are Common Results?
Results are typically reported as a numerical value representing the enzyme activity level. While reference ranges can vary by lab, elevated levels above normal may signal heart muscle injury. Your doctor will interpret results in the context of your symptoms and medical history.
Reference range
Asialotransferrin is normally undetectable or present at very low levels in CSF. Presence of asialotransferrin (carbohydrate-deficient transferrin, CDT) in CSF indicates leakage of serum-derived transferrin across a disrupted blood-brain barrier or localized cerebral production.N/A
No special patient preparation required. Inform the ordering physician of any recent lumbar puncture, trauma, or neurological procedures.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Why This Test Matters
Short name
CPK-MB (or Cardiac CPK)
Frequently asked questions
How long does it take to get results from this test?
Can lifestyle changes affect CPK-MB levels?
Is this test painful?
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