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T-wave amplitude (serum/plasma)

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

This test measures the electrical activity of your heart’s T-waves in serum or plasma, often used to assess heart health and detect potential arrhythmias or electrolyte imbalances.

Quick summary

["Your T-wave voltage helps doctors evaluate heart rhythm and electrical function."]

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

Key facts at a glance

LOINC
10137-8
Short code
T' wave Amp L-V2
Synonyms
T' wave Amp L-V2
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
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

What Is a T-Wave?

The T-wave in an electrocardiogram (ECG or EKG) represents the final phase of a heart’s electrical cycle, where the heart’s ventricles relax. In serum/plasma, measuring T-wave amplitude can reflect underlying heart cell health or metabolic conditions.

Why Might This Test Be Ordered?

Your healthcare provider may order this test if you have symptoms like chest pain, irregular heartbeat, or if they suspect conditions like long QT syndrome, electrolyte disturbances, or heart muscle damage.

How Is This Test Performed?

Blood is drawn from a vein, typically in your arm, and sent to a lab. The serum or plasma is analyzed for electrical activity related to T-waves, often using advanced imaging or biochemical methods to detect subtle changes.

What Does a Result Mean?

Results may indicate normal heart electrical function or suggest potential issues like abnormal heart rhythms, metabolic stress, or other cardiac conditions. Interpretation depends on your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: T-Wave Amplitude in Heart Health

Short name

T-wave Voltage

Frequently asked questions

How often will I need this test?
This test is usually performed as part of a broader cardiac evaluation, often alongside an ECG. Frequency depends on your medical history, symptoms, and doctor’s recommendations.
What are the risks of this test?
The primary risk is mild discomfort from the blood draw, such as bruising or slight pain. There are no known risks from the serum/plasma analysis itself.
Can I eat or drink before this test?
No special preparation is needed for this test, but follow your doctor’s instructions regarding medications or dietary restrictions if they apply to your specific situation.
  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