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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 level of creatine kinase, an enzyme found in heart, muscle, and brain cells. It helps assess damage to these tissues.

Quick summary

["CPK/CK helps identify muscle or heart injury by detecting enzyme release into your bloodstream."]

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

Key facts at a glance

LOINC
53298-6
Short code
Tri-Phos Cry # Ur Comp Assist
Synonyms
Tri-Phos Cry # Ur Comp Assist
Category
electrolyte
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
computer-assisted
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Matters: Muscle and Heart Health

Creatine kinase (CPK/CK) is released into your blood when muscle or heart tissue is damaged. High levels may signal recent injury, such as a heart attack, muscle strain, or other conditions affecting these organs.

Common Causes of Elevated Levels

Elevated CPK/CK can occur after exercise, muscle injuries (e.g., cramps, strains), or conditions like myopathies (muscle diseases). In the heart, it’s often linked to myocardial infarction (heart attack).

When You Might Need This Test

Your doctor may order CPK/CK if you have symptoms like chest pain, muscle weakness, or unexplained fatigue, especially after trauma or exercise.

When Results Might Be Low

Low CPK/CK levels are less common but may occur in severe muscle wasting, certain metabolic disorders, or during pregnancy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CPK/CK Activity

Frequently asked questions

How often should I get this test?
CPK/CK is typically checked as needed—often after trauma, surgery, or symptoms of muscle/heart issues. Your doctor will determine frequency based on your health history and concerns.
What does a normal range mean for my health?
A normal range doesn’t guarantee no damage; it’s a baseline. High levels may prompt further testing (e.g., heart scans, muscle biopsies) to investigate causes.
Can diet or exercise affect CPK/CK levels?
Yes—intense exercise or muscle strain can temporarily raise CPK/CK. Avoiding extreme activity before testing may help get a clearer picture.
  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