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Cardiac Troponin I, Serum (High-Sensitivity)

Published: August 9, 2026Updated: August 17, 2026

This test measures a protein released by heart muscle when it is damaged, often due to a heart attack. It helps doctors assess whether you may have suffered heart injury.

Quick summary

["High levels can signal recent or ongoing heart damage; low or normal levels suggest heart tissue is likely intact."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
38482-6
Short code
CK MB SerPl Ql
Synonyms
CK MB SerPl Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
22
Ref high
198
Critical range
— – 10000 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82553
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

High-sensitivity cardiac troponin I (hs-cTnI) is used to detect even small amounts of heart muscle damage. Unlike older tests, this version can detect very low levels, making it more accurate for diagnosing conditions like a heart attack, unstable angina, or heart strain from stress or illness.

When It’s Ordered

Your doctor may order this test if you have symptoms like chest pain, shortness of breath, or other signs of heart trouble. It’s also used in monitoring people with known heart disease or those recovering from a heart procedure.

What to Expect

A blood sample is taken from a vein, usually in your arm. You may feel a small pinch, but it’s quick. Results are compared to a reference range to determine if your levels are elevated.

Possible Results

If your levels are above normal, it may indicate heart damage. If they’re normal, your heart muscle is likely not damaged at that time. Follow-up tests or doctor’s guidance will help clarify next steps.

Reference range

Adult males: 22-198 U/L; Females: 22-198 U/LN/A

Specimen: serum

No special preparation required. Inform provider of any chest pain or symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

hs-cTnI (Serum)

Frequently asked questions

What does a high level of cardiac troponin I mean?
A high hs-cTnI level strongly suggests recent or ongoing heart muscle injury, such as from a heart attack, severe stress on the heart, or other conditions like myocarditis. It’s a key marker for diagnosing these issues and guiding treatment decisions.
Can low or normal levels rule out heart problems?
While low or normal levels mean your heart muscle is likely not damaged at this time, they don’t completely rule out heart issues. Some conditions, like mild heart strain or early heart attack, may still require further testing or observation.
How often should I get this test?
Your doctor will determine how often you need this test based on your symptoms, medical history, and overall health. It may be done once or repeated over time if needed for monitoring.
  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 17, 2026. · Read our editorial policy