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Serum Creatinine Phosphokinase (CPK) or Serum Creatine Kinase (CK) Activity

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

This test measures the activity of creatine kinase, an enzyme found in heart, muscle, and brain cells. It helps assess damage to these tissues.

Quick summary

["Helps identify muscle, heart, or brain injury by detecting elevated enzyme levels after damage occurs."]

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

Key facts at a glance

LOINC
27395-3
Short code
S pneum Da 18C IgG Ser-mCnc
Synonyms
S pneum Da 18C IgG Ser-mCnc
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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?

Creatine kinase (CK) is an enzyme that helps convert creatine to phosphocreatine, providing energy to cells. When tissues like the heart, skeletal muscles, or brain are injured, CK leaks into the bloodstream, increasing its levels. This test quantifies the amount of CK activity in your serum to detect such damage.

Why Might You Need This Test?

Doctors may order a CK test to investigate symptoms like chest pain, muscle weakness, or neurological issues. It’s also used after heart attacks, strokes, or injuries to monitor recovery and identify complications.

When Is This Test Typically Done?

A CK test is often performed during emergencies (e.g., suspected heart attack) or as part of routine checks for conditions like myopathy (muscle disorders) or neurological diseases. Results may be checked repeatedly if ongoing monitoring is needed.

What to Expect Before the Test

No special preparation is usually required, but you may be asked to avoid strenuous exercise or certain medications that could affect results. If you’re taking blood thinners or muscle relaxants, inform your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK/CK Serum

Frequently asked questions

What Does Elevated or Low CK Levels Mean?
Elevated CK levels often signal tissue damage, such as from a heart attack, muscle strain, or stroke. Different muscle types (e.g., cardiac vs. skeletal) may show varied patterns. Low CK levels could indicate muscle atrophy or certain genetic disorders.
How Long Until Results Are Ready?
Results are typically available within 24–48 hours, depending on lab processing. Your doctor will discuss them during your follow-up visit.
Can Diet or Exercise Affect This Test?
Moderate exercise is unlikely to impact results, but intense physical activity shortly before testing may raise CK levels. Avoiding alcohol or muscle-strenuous activities 24 hours prior can help stabilize readings.
  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