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Neurofilament Light Chain (NfL) 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, which can help assess nerve damage or disease progression.

Quick summary

["Helps track nerve health and disease impact in conditions like multiple sclerosis or traumatic brain injury."]

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

Key facts at a glance

LOINC
39022-9
Short code
S neurona Ab Ser Ql IF
Synonyms
S neurona Ab Ser Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 It’s Done

Doctors may order this test if you have symptoms of nerve damage, such as weakness, numbness, or balance issues. It’s often used in research or specialized care for neurological conditions like multiple sclerosis, Alzheimer’s disease, or spinal cord injuries.

What to Expect During the Test

A small blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and doesn’t require special preparation. Results are analyzed to check for elevated levels of NfL, which may indicate nerve cell damage.

How Results Are Interpreted

While there’s no single reference range, higher than normal levels of NfL often suggest nerve injury or disease activity. Your doctor will compare your results to your medical history and symptoms to guide further care.

Common Conditions Monitored

This test is particularly useful for tracking progression or response to treatment in conditions like multiple sclerosis, traumatic brain injury, Alzheimer’s disease, or other neurodegenerative disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Neurofilament light chain is a protein released when nerve cells are damaged. Elevated levels in the blood can indicate ongoing nerve injury, help diagnose certain neurological conditions, or monitor disease progression over time. It’s not a diagnostic test alone but a useful tool in specialized care plans.

Short name

NfL Blood Test

Frequently asked questions

What does an elevated NfL level mean?
An elevated NfL level may suggest nerve damage or disease activity, such as in multiple sclerosis, traumatic brain injury, or neurodegenerative conditions. Your doctor will consider your symptoms, medical history, and other test results to interpret the results.
Does this test require fasting?
No fasting is required for this blood test. You can eat and drink normally before your appointment.
How long does it take to get results?
Results are typically available within a few days to a week, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
  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