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Serum Creatinine Phosphokinase (CPK) Activity

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

This test measures the activity of an enzyme called creatine phosphokinase (CPK), which helps assess muscle, heart, and brain health. CPK levels can rise if tissues are damaged.

Quick summary

["CPK helps identify muscle, heart, or nerve damage by measuring enzyme release into the bloodstream."]

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

Key facts at a glance

LOINC
111286-1
Short code
MuV Ab Msmt Ser
Synonyms
MuV Ab Msmt Ser
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Your doctor may order this test to check for conditions affecting your muscles, heart, or nervous system. Elevated CPK levels can signal muscle injuries, heart attacks, or other illnesses like myopathies or stroke.

What Does a High or Low CPK Level Mean?

High CPK levels may indicate muscle damage (e.g., from exercise, injury, or certain diseases), heart problems, or nerve disorders. Very low levels are rare but could suggest muscle wasting or certain metabolic disorders.

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 CPK activity is measured using an immunoassay or enzymatic method.

What Are Common Causes of Abnormal Results?

Elevated CPK can result from overexertion, muscle strains, infections, or conditions like myositis. Heart attacks, seizures, or certain medications may also raise CPK levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

CPK levels can help diagnose muscle disorders, detect heart damage, or monitor conditions like muscular dystrophy or rhabdomyolysis. However, they’re often used alongside other tests for a full picture.

Short name

CPK (Serum)

Frequently asked questions

What triggers CPK levels to rise?
CPK levels can rise due to physical activity, muscle injuries, infections, or certain medications. Heart-related events, like a heart attack, can also temporarily increase CPK.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time.
Can CPK levels be affected by diet or supplements?
Diet or supplements alone rarely affect CPK levels, but certain medications (e.g., statins, steroids) or muscle-strengthening activities may influence results.
  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