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Serum Creatinine Phosphokinase (CPK) Activity

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

This test measures the activity of an enzyme called creatine phosphokinase (CPK), which helps your body produce energy. High levels may suggest muscle damage or other health concerns.

Quick summary

["CPK helps identify muscle injury or related conditions by measuring enzyme activity in your blood."]

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

Key facts at a glance

LOINC
53006-3
Short code
ENA PCNA Ab Titr Ser IF
Synonyms
ENA PCNA Ab Titr Ser IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 Is Done

Your doctor may order this test to check for muscle damage, such as from exercise, injury, or conditions like myopathy. It can also help evaluate heart-related issues, like a heart attack, or monitor muscle disorders.

What to Expect Before the Test

No special preparation is needed, but avoid intense exercise 24 hours before testing. If you’re taking medications that affect muscle function, let your doctor know.

How the Test Works

A blood sample is taken from a vein in your arm. The lab measures CPK levels using an immunoassay or enzymatic method to detect enzyme activity.

Possible Results & Interpretation

Results are compared to a general reference range, but your doctor will interpret them based on your health history and symptoms. Elevated levels may indicate muscle injury, heart problems, or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated CPK Levels May Signal

Short name

CPK (Serum)

Frequently asked questions

What might cause elevated CPK levels?
Elevated CPK can result from muscle damage (e.g., from strenuous exercise, injury, or certain medications). It may also be linked to heart issues, such as a heart attack, or neurological disorders like myasthenia gravis.
What might cause low CPK levels?
Low CPK levels are less common but may occur in rare genetic muscle disorders or severe liver/kidney disease. Your doctor will assess this in context with other tests and symptoms.
How often should I get this test?
Your doctor will determine frequency based on your health needs—this may include routine checks for muscle-related conditions or follow-up after a suspected injury.
  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