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Serum Creatinine Phosphokinase (CPK) Activity (Total)

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

This test measures the activity of Creatine Phosphokinase (CPK), an enzyme found in heart, skeletal muscle, and brain tissues. It helps assess muscle damage, heart health, or neurological conditions.

Quick summary

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

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

Key facts at a glance

LOINC
85988-4
Short code
S pneum Da 12F Ab 2:1 Ser-Rto
Synonyms
S pneum Da 12F Ab 2:1 Ser-Rto
Category
coagulation
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

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 evaluate conditions like heart attacks, muscle injuries, or neurological disorders.

Why Is This Test Done?

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 trauma or surgery.

When Might You Need This Test?

You might need this test if you have recent muscle pain, a suspected heart issue, or if you’re recovering from surgery or an injury. It’s sometimes included in broader health screenings or follow-ups.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your doctor specifies it. Wear loose clothing for easy access to your arm.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CPK levels often indicate muscle damage, heart strain, or neurological stress. Very high levels can signal severe conditions like a heart attack, rhabdomyolysis (a serious muscle breakdown), or stroke. Low levels alone rarely indicate a problem unless part of a broader evaluation.

Short name

CPK Serum

Frequently asked questions

How long does it take to get results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing time. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
Most of the time, you can eat and drink normally unless your doctor instructs otherwise. Some labs may ask for fasting, so check with them beforehand.
Does CPK test hurt?
The blood draw itself is quick and may cause mild discomfort, but it’s usually over in a few minutes. Most people don’t feel significant pain afterward.
  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