Serum Creatinine Phosphokinase (CPK) Isoenzyme Ratio (Lactate Dehydrogenase (LDH)-Dependent)
This test measures the ratio of specific muscle enzyme fragments in your blood, which can help identify which muscle enzymes are elevated and may indicate muscle damage or certain conditions.
["This ratio helps pinpoint the source of muscle enzyme elevation for better diagnosis and treatment planning."]
Key facts at a glance
- LOINC
- 6479-0
- Short code
- MuV IgM Titr Ser IF
- Synonyms
- MuV IgM Titr Ser IF
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- if
- 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 This Test Measures
The test looks at the breakdown products of creatine phosphokinase (CPK), an enzyme primarily found in heart, skeletal, and smooth muscle cells. When muscle tissue is damaged, CPK is released into the bloodstream. This test specifically examines the ratio involving lactate dehydrogenase (LDH)-dependent fragments, which may reflect different types of muscle injury or disease processes.
Why It Matters in Diagnosis
Evaluating this ratio can help distinguish between types of muscle injury (e.g., cardiac vs. skeletal muscle damage) or conditions like myocarditis, rhabdomyolysis, or certain metabolic disorders. It may also be used alongside other tests to confirm or refine a diagnosis.
Common Uses and Clinical Context
This test is often used in patients with unexplained muscle weakness, chest pain, or symptoms suggesting heart or muscle injury. It may also be part of a broader evaluation for conditions like stroke, severe infections, or toxic exposures that affect muscle tissue.
Sample Collection and Preparation
A blood sample is drawn from a vein, typically in the arm. The sample is processed to separate serum, which is then analyzed. No special preparation is needed, but fasting may be advised depending on the clinical context.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated CPK isoenzyme ratios can signal muscle injury, inflammation, or metabolic disturbances. For example, certain patterns may suggest cardiac muscle damage (e.g., myocardial infarction), while others may point to skeletal muscle disorders. This test is particularly useful when other markers are inconclusive or when differentiating between types of muscle involvement.
Short name
CPK Isoenzyme Ratio (LDH-based)
Frequently asked questions
What does a high or low result mean?
Does this test require fasting?
How long will results take to return?
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