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Serum Creatinine Phosphokinase (CPK) Mass Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of Creatine Phosphokinase (CPK), an enzyme found in heart, muscle, and brain cells, in your blood serum. It helps assess muscle damage or heart-related conditions.

Quick summary

["CPK levels can indicate muscle injury or heart problems."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
99364-2
Short code
Ovalb IgG-mCnc
Synonyms
Ovalb IgG-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Does CPK Measure?

CPK is an enzyme that plays a role in energy production in cells. When muscle tissue is damaged (e.g., from injury, exercise, or conditions like myositis), CPK leaks into the bloodstream. Elevated levels may signal muscle injury or other health issues.

Why Might Your Doctor Order This Test?

Your doctor may request CPK testing if you have symptoms like muscle pain, weakness, or unexplained fatigue. It’s also used to monitor conditions affecting heart or muscle function, such as heart attacks, muscle disorders, or certain infections.

Common Reasons for Testing

Common reasons include diagnosing muscle injuries, evaluating heart-related symptoms, checking for conditions like myopathy, or monitoring treatment responses for conditions like polymyositis.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to avoid strenuous activity or certain medications for a few days before testing. Always follow your healthcare provider’s instructions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CPK levels can help identify muscle or heart damage early, but they’re often used alongside other tests for a full picture. High levels may require further evaluation to determine the cause, such as trauma, infections, or metabolic disorders.

Short name

CPK (Serum)

Frequently asked questions

What are normal CPK levels?
There are no specific reference ranges provided here since they can vary by lab and individual factors. Your results will be compared to your lab’s standards and discussed with your doctor.
Can CPK levels change with diet or exercise?
Yes, physical activity or intense exercise can temporarily raise CPK levels. Avoid strenuous activity before testing if instructed by your provider.
What symptoms might indicate high CPK levels?
Symptoms like muscle pain, weakness, or fatigue may accompany elevated CPK levels, but not everyone with high CPK has symptoms. Your doctor will interpret results in context with your health history.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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