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Serum Creatinine Phosphokinase (CPK) Isoenzyme Assay (Specifically: Cardiac Troponin I or Myoglobin, via Immunoassay)

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

This test measures specific enzymes released from heart muscle cells when they are damaged, helping assess potential heart injury or stress.

Quick summary

["Helps detect heart-related damage or muscle strain by tracking key protein markers in your blood."]

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

Key facts at a glance

LOINC
48075-6
Short code
GH 2.5h p betaxolol+Gc SerPl-aCnc
Synonyms
GH 2.5h p betaxolol+Gc SerPl-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 for Your Health

Your doctor may order this test if you have symptoms like chest pain, shortness of breath, or after a heart procedure. It helps identify if your heart muscle has been damaged or if your heart is working harder than usual.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. Avoid strenuous activity or heavy meals 24 hours before testing if instructed by your provider.

What the Results Mean

Elevated levels may signal recent heart injury, muscle strain, or conditions like a heart attack, stroke, or severe muscle disease. Results are interpreted by your healthcare team based on your symptoms and medical history.

Common Causes of Abnormal Results

High levels can occur after heart attacks, heart surgery, or intense physical exertion. Low levels are less common but may indicate muscle wasting or certain metabolic disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

This test plays a critical role in diagnosing conditions like myocardial infarction (heart attack), myocarditis (heart inflammation), or rhabdomyolysis (severe muscle breakdown). Early detection can guide urgent treatment and prevent complications.

Short name

CPK Cardiac Isoenzyme

Frequently asked questions

What triggers this test?
Your doctor may order this test if you have symptoms like chest pain, unusual fatigue, or if you’ve had recent trauma, surgery, or a heart procedure.
How soon will I get my results?
Results are typically available within 24 to 48 hours, depending on lab processing times. Your doctor will discuss them with you during your follow-up visit.
Can I eat or drink before this test?
Standard blood tests like this one don’t require fasting, but follow your doctor’s instructions if they specify any restrictions for your specific test.
  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