Skip to content

Neurofilament light chain (NF-L) in serum/plasma

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

This test measures the levels of neurofilament light chain, a protein found in nerve cells. It helps assess nerve damage or degeneration.

Quick summary

["Neurofilament light chain testing may help diagnose or monitor conditions affecting nerves."]

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

Key facts at a glance

LOINC
98704-0
Short code
F-wave motor NC Pnl Nerve
Synonyms
F-wave motor NC Pnl Nerve
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

What Is Neurofilament Light Chain?

Neurofilament light chain (NF-L) is a protein that makes up the cytoskeleton of nerve cells. When nerves are damaged, these proteins can leak into the bloodstream. This test detects their presence to evaluate nerve health.

Why Might You Need This Test?

Doctors may order this test to investigate symptoms like weakness, numbness, or other neurological issues. It can help diagnose conditions such as multiple sclerosis, amyotrophic lateral sclerosis (ALS), or other neurodegenerative diseases.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is then sent to a lab for analysis using advanced techniques to measure NF-L levels.

What Do Results Mean?

Results are not typically provided in absolute numbers, as reference ranges vary by lab and method. Instead, they are often compared to baseline or clinical context to determine if nerve damage is present or worsening.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

NF-L (Serum/Plasma)

Frequently asked questions

How often will I need this test?
The frequency depends on your condition and treatment plan. Your healthcare provider will determine how often you need follow-up testing based on your symptoms and test results.
What are the possible side effects of this blood test?
Most people experience only minor discomfort or bruising at the injection site. Rarely, there may be a slight swelling or redness.
Can I eat or drink before this test?
You can typically eat and drink normally before the test unless your doctor specifies otherwise. Follow any specific instructions they provide for your convenience.
  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