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Serum Creatinine Phosphokinase (CPK) Activity

Published: August 9, 2026Updated: August 17, 2026

This test measures the activity of an enzyme called creatine phosphokinase (CPK), which helps assess muscle, heart, or brain health by detecting damage.

Quick summary

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

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
40093-7
Short code
PT 3h p chal PPP
Synonyms
PT 3h p chal PPP
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
44
Ref high
147
Critical range
20 N/A – 400 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
coag-tissue-factor-induced
CPT
84075
SNOMED
27550007
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 Matters

CPK is found in high amounts in heart, skeletal, and brain tissues. When cells are damaged, CPK leaks into the bloodstream, raising its levels. This test helps doctors identify conditions like heart attacks, muscle injuries, or strokes.

What to Expect Before the Test

No special preparation is needed, but avoid intense exercise or strenuous activity 24 hours before testing to get the most accurate results.

Common Causes of Elevated CPK Levels

High CPK levels may occur due to muscle injuries (e.g., from exercise, trauma), heart attacks, or neurological disorders like stroke. Certain medications or genetic conditions can also affect CPK levels.

What to Expect After the Test

You’ll likely receive results within a few days. Follow-up may include additional tests or doctor’s visits if abnormal results are found.

Reference range

Adult: 44-147 U/LN/A

Specimen: plasma

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated CPK is critical in diagnosing conditions like myocardial infarction (heart attack), rhabdomyolysis (severe muscle breakdown), or neuromuscular disorders. Low CPK may indicate muscle wasting or certain genetic disorders.

Short name

CPK (Serum)

Frequently asked questions

How long does it take to get CPK test results?
Results are typically available within 24 to 72 hours, depending on your lab’s processing time.
Can diet or exercise affect CPK levels?
Moderate exercise may slightly raise CPK, but intense or prolonged activity can cause temporary spikes. Avoid extreme workouts before testing for accuracy.
What if my CPK level is high?
A doctor will review your results alongside symptoms and other tests. Elevated CPK may prompt further evaluation for muscle damage, heart issues, or other underlying causes.
  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 17, 2026. · Read our editorial policy