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Serum Creatinine Phosphokinase (CPK) Isoenzyme Assay (Total CPK)

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

This test measures the total amount of creatine phosphokinase (CPK), an enzyme found in heart, muscle, and brain cells. It helps assess damage to these tissues.

Quick summary

CPK levels can indicate muscle, heart, or brain injury.

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

Key facts at a glance

LOINC
33397-1
Short code
N men sg A+C+W135+Y Ag Ser Ql LA
Synonyms
N men sg A+C+W135+Y Ag Ser Ql LA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
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 Is Done

Your doctor may order this test if you have symptoms like chest pain, muscle weakness, or unexplained fatigue. It can also be used to monitor conditions affecting muscle or heart health, such as heart attacks, muscle injuries, or certain neurological disorders.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re taking medications that affect muscle function, let your doctor know.

What the Results Mean

Elevated CPK levels may suggest recent muscle injury, heart damage, or other conditions affecting these tissues. Your doctor will interpret results in relation to your symptoms and medical history.

Common Conditions Linked to CPK Levels

High CPK levels are often seen after muscle strain, heart attacks, or conditions like myositis (inflammation of muscles). Low levels may rarely indicate certain metabolic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CPK is important for diagnosing and guiding treatment of muscle or heart injuries, but results alone don’t diagnose a condition. Your doctor will consider the full clinical picture.

Short name

Total Creatine Phosphokinase (CPK)

Frequently asked questions

What causes CPK levels to rise?
CPK levels can rise due to muscle damage from exercise, injuries, or conditions like rhabdomyolysis (severe muscle breakdown). Heart attacks or strokes can also elevate CPK in some cases.
How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing time.
Can CPK levels be affected by diet or exercise?
Yes, intense exercise or muscle strain can temporarily raise CPK levels. Avoid heavy exercise 24 hours before testing if possible.
  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