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Neurofilament Light Chain (NfL) in Cerebrospinal Fluid (CSF)

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

This test measures a protein found in nerve cells, which can help identify damage or disease in the brain or spinal cord.

Quick summary

["NfL CSF helps assess neurological conditions by detecting nerve fiber injury."]

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

Key facts at a glance

LOINC
31530-9
Short code
Neuronal Ab CSF-aCnc
Synonyms
Neuronal Ab CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What Is Neurofilament Light Chain (NfL)?

Neurofilament Light Chain (NfL) is a protein that makes up the cytoskeleton of nerve cells. When nerves are injured or diseased, NfL can leak into the cerebrospinal fluid (CSF). Measuring NfL helps doctors determine if there’s damage to the nervous system, such as in multiple sclerosis, traumatic brain injury, or other neurological disorders.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like memory loss, weakness, vision problems, or other signs of nerve damage. It’s also used to monitor conditions like multiple sclerosis or to check for nerve injury after trauma or surgery.

How Is the Test Performed?

A small amount of cerebrospinal fluid is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then sent to a lab for analysis. The test measures the concentration of NfL in the CSF.

What Are Possible Results?

Results are compared to a reference range for healthy individuals. Higher than expected levels may suggest nerve damage or disease, while lower levels may indicate normal nerve health or other conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

NfL CSF

Frequently asked questions

How often will I need this test?
This test is typically done once or multiple times depending on your symptoms, diagnosis, or treatment plan. Your doctor will determine how often you need it based on your specific situation.
What do my results mean?
Your results will be discussed with your doctor, who will interpret them in the context of your medical history and symptoms. Elevated NfL levels may point to conditions like multiple sclerosis, brain injuries, or neurodegenerative diseases.
Can I prepare for this test?
No special preparation is needed for this test. You may need to stay still for a short period after the procedure to avoid complications, but you can resume normal activities afterward.
  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