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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 or heart injury and guide treatment decisions."]

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

Key facts at a glance

LOINC
2730-0
Short code
PTH-C SerPl-mCnc
Synonyms
PTH-C SerPl-mCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
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 This Test Measure?

CPK is released into the bloodstream when muscle or heart tissue is damaged. High levels may suggest recent injury, exercise-induced stress, or underlying conditions like myocarditis or rhabdomyolysis. This test is often used alongside other markers to diagnose or monitor these conditions.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like muscle pain, weakness, chest pain, or if you’re recovering from surgery, trauma, or a heart procedure. It can also help evaluate conditions like heart attacks, muscle disorders, or nerve damage.

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 test if it’s part of a broader metabolic or cardiac evaluation. Avoid strenuous exercise or certain medications that could affect results.

What Happens During the Test?

A healthcare professional will draw blood from a vein in your arm. The sample is sent to a lab for analysis. The process takes about 15 minutes, and you may feel slight discomfort but no lasting effects.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: serum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

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 recent or ongoing muscle or heart damage. Common causes include intense exercise, muscle injuries, heart attacks, or conditions like myositis. Your doctor will review your symptoms and other test results to determine the cause.
What If My CPK Level Is Normal?
If your CPK level is within the expected range, it generally means there’s no immediate evidence of muscle or heart damage. However, if you’ve had symptoms like unexplained muscle pain or fatigue, further evaluation may be needed to rule out underlying conditions.
Can CPK Levels Change Over Time?
Yes, CPK levels can fluctuate based on activity level, recent injury, or underlying health conditions. If your results are abnormal, your doctor may recommend follow-up tests or adjustments to your treatment plan.
  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