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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 assess muscle, heart, and brain health. CPK levels can rise if tissues are damaged.

Quick summary

["CPK helps detect muscle or heart damage by measuring enzyme release into the bloodstream."]

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

Key facts at a glance

LOINC
110954-5
Short code
EBV EA IgG Msmt Ser
Synonyms
EBV EA IgG Msmt Ser
Category
chemistry
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

Why Is This Test Done?

Your doctor may order a CPK test to check for muscle injuries, heart problems (such as a heart attack), or nerve conditions. It can also help diagnose conditions like myopathy (muscle disease) or monitor treatment effectiveness for certain illnesses.

What to Expect Before the Test

No special preparation is needed. You may eat and drink as usual. If you’re taking medications, ask your doctor whether to stop them temporarily, as some can affect results.

How the Test Works

A blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where the CPK enzyme activity is measured using an immunoassay or enzymatic method.

What the Results Mean

Results are typically reported in units per liter (U/L) or milliliters (mU/mL). Higher than normal levels may indicate muscle injury, heart damage, or other health concerns. Your doctor will interpret results in relation to your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Elevated CPK Levels Can Signal Underlying Conditions

Short name

CPK Serum

Frequently asked questions

What causes elevated CPK levels?
Elevated CPK levels are often due to muscle damage (e.g., from exercise, injury, or illness), heart attacks, or certain medications. Rarely, high levels can be linked to nerve disorders or metabolic conditions.
Can CPK levels ever be low?
Yes, very low CPK levels may suggest muscle wasting, severe malnutrition, or rare genetic disorders. However, this is less common and usually requires further evaluation.
How often should I get this test?
Your doctor will determine testing frequency based on your symptoms, medical history, and treatment plan. Regular monitoring may be needed if you have chronic conditions like muscle disorders or heart disease.
  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