Skip to content

Nerve Conduction Velocity (NCV) with Latency Assessment

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

This test measures how quickly electrical signals travel along your nerves and checks for delays (latency) that may indicate nerve damage or disease.

Quick summary

Assesses nerve function and potential nerve damage with speed and timing measurements.

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

Key facts at a glance

LOINC
98650-5
Short code
Sensory NC velocity L LACN
Synonyms
Sensory NC velocity L LACN
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nerve-conduction
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 Does This Test Measure?

Nerve conduction velocity (NCV) tests record the speed and strength of electrical signals traveling along your peripheral nerves. Latency measures how long it takes for these signals to reach a muscle or skin site. These tests help diagnose conditions like neuropathy, nerve compression, or demyelinating diseases.

How Is the Test Performed?

You’ll lie on an exam table while electrodes are placed on your skin at specific nerve entry and exit points. A mild electrical stimulus sends signals through your nerves, and a machine records the response. Some tests may involve muscle stimulation to assess reflexes. The procedure is quick but may cause mild discomfort.

When Might You Need This Test?

Your doctor may recommend NCV testing if you have symptoms like tingling, numbness, weakness, or pain in your arms or legs. It’s also used to evaluate conditions like diabetic neuropathy, carpal tunnel syndrome, Guillain-Barré syndrome, or multiple sclerosis.

What Are Common Findings?

Results may show slowed nerve conduction speeds (hypoexcitability) or delayed latency, which can indicate nerve damage, inflammation, or structural issues. Abnormal findings often prompt further evaluation or treatment adjustments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Why It Matters

Frequently asked questions

How long does the test take?
The NCV test typically takes about 30 to 60 minutes, depending on the number of nerves assessed. Multiple nerves may be tested in one session.
What preparation is needed before the test?
No special preparation is usually required, but you may need to avoid caffeine or nicotine for 2–3 hours before testing. Wear loose clothing and avoid lotions on the test areas.
Will the test hurt?
You may feel a mild tingling or slight discomfort from the electrical stimulation, but it’s generally not painful. Some patients report a brief muscle twitch or cramp during testing.
  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