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Serum Creatinine Phosphokinase (CPK) Activity (Total)

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

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

Quick summary

["CPK levels can signal muscle or heart injury; higher levels may indicate damage to these tissues."]

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

Key facts at a glance

LOINC
93645-0
Short code
LV EF A4C SP A-L
Synonyms
LV EF A4C SP A-L
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-d-a-c-calc-by-single-plane-area-length-method
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 or heart tissue is damaged, CPK leaks into the bloodstream, raising its levels. This test helps doctors identify conditions like heart attacks, muscle injuries, or other illnesses affecting these organs.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like chest pain, muscle weakness, or unexplained fatigue. It’s also used to monitor conditions like heart disease, muscle disorders, or after injuries.

When Are Results Typically Available?

Results are usually available within 24 to 48 hours, depending on your lab’s processing time.

What Are Common Causes of Abnormal Results?

Elevated CPK levels may occur due to muscle injuries (e.g., exercise, trauma), heart attacks, or certain illnesses like myopathies. Low levels might indicate muscle wasting or certain metabolic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK Serum

Frequently asked questions

What does a high CPK level mean?
A high CPK level suggests potential muscle or heart damage. It could signal conditions like a heart attack, severe muscle injury, or other illnesses affecting these tissues. Your doctor will review the results alongside your symptoms and other tests.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition, symptoms, or treatment plan. Regular monitoring may be needed if you have a history of heart disease, muscle disorders, or recent injuries.
Can lifestyle changes affect CPK levels?
Yes, activities like intense exercise, muscle strain, or certain medications (e.g., statins) can temporarily raise CPK levels. Avoiding overexertion or discussing medications with your doctor can help manage 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