DIAGNOSTIC TEST 994

Neurofilament Light (NfL)

Diagnostic test for NfL. For suspicion of neuronal damage in the CNS or PNS.

urgent

Available as urgent test with results within 48 h.

Indication

Suspicion of neuronal damage in the CNS or PNS

Sample material

Serum

  • Minim. volume: 0,5 mL

CSF

  • Minim. volume: 0,5 mL

EDTA-plasma

  • Minim. volume: 0,5 mL

Transport

Serum

  • Within Sweden: room temperature
  • International: room temperature

CSF

  • Within Sweden: room temperature
  • International: room temperature

EDTA plasma

  • Within Sweden: room temperature/frozen (stable for 48h in room temperature)
  • International: room temperature/frozen (stable for 48h in room temperature)

Method

Single Molecule Array (SIMOA)

Reference interval

Serum/EDTA plasma

Age

Reference interval

18-40 years:

2.8 – 9.7 ng/L

41-65 years:

4.6 – 21.4 ng/L

>65 years:

7.5 – 53.8 ng/L

CSF

Age

Reference interval

<30 years:

<380 ng/L

30-39 years:

<560 ng/L

40-59 years:

<890 ng/L

≥60 years:

<1850 ng/L

Result

Results are reported as a concentration in ng/L.

Interpretation

NfL is an axonal protein in both the central and peripheral nervous systems (CNS and PNS). During axonal damage in CNS, NfL leaks into CSF and elevated levels can then often also be detected in blood (serum/plasma). NfL levels in blood are several times lower than in CSF but the correlation is high. Elevated levels of NfL in blood can also reflect the degree of axonal damage in PNS. Analysis in plasma gives approximately 10% lower NfL levels than in serum.

Elevated levels of NfL are a nonspecific damage marker and do not indicate the underlying cause. Since the level varies greatly between individuals in the normal population and increases with age, the reference intervals are wide and age-related. It is therefore appropriate that patients are monitored individually. >20% difference in NfL levels between two samples is considered significant. After acute damage it takes up to 6 months for the NfL level to return to the individual's baseline value, provided that no new damage occurs.

In dementia, mildly elevated levels in CSF are usually seen which are somewhat more pronounced in frontotemporal and vascular dementia compared to Alzheimer's disease. However, the experience of serum/plasma NfL in these disease groups is limited.

Significantly elevated levels indicate widespread diffuse axonal damage and can be seen in several conditions, e.g. encephalitis. High levels can also be seen in ALS with upper motor neuron damage. After cerebral infarction, elevated levels of NfL can be found several weeks after the acute stage due to the secondary tissue damage.

In case of unclear cause of injury in the CNS, NfL is investigated together with other brain injury markers in CSF: GFAp (astrocyte injury marker), Tau (cortical injury marker), Beta-amyloid (dementia marker), and S-100 (acute brain injury). In addition, analysis of neuron-specific enolase (NSE) in serum may be of value in acute brain injury and is also a marker for some neuroendocrine tumors.

References

  • Jens Kuhle et al. Neurology. 2019. Blood neurofilament light chain as a biomarker of MS disease activity and treatment response. PMID: 30737333
  • Hviid CVB et al. Scand J Clin Lab Invest. 2020. Reference interval and preanalytical properties of serum neurofilament light chain in Scandinavian adults. PMID: 32077769
  • Khalil M et al. Nat Commun. 2020. Serum neurofilament light levels in normal aging and their association with morphologic brain changes. PMID: 32041951
  • Halbgebauer S et al. J Neurol Neurosurg Psychiatry. 2022. Comparison of CSF and serum neurofilament light and heavy chain as differential diagnostic biomarkers for ALS. PMID: 34417339
  • Park Y et al. Int J Mol Sci. 2024.Tau, Glial Fibrillary Acidic Protein, and Neurofilament Light Chain as Brain Protein Biomarkers in Cerebrospinal Fluid and Blood for Diagnosis of Neurobiological Diseases. PMID: 38928000
  • Glāzere I et al. Sci Rep. 2026. Plasma neurofilament light chain is associated with clinical instability in chronic autoimmune neuropathies. PMID: 41699397

Included in these panels

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How to order

This test is available worldwide for hospitals, clinics, and physicians.

  1. Print and complete the request form

    Download the request form. Clearly state the name and phone number of the referring hospital, clinic, or physician. If you are a new customer, please also include a completed customer information form.

  2. Prepare your samples

    Serum: At least 0.5 mL serum (plain serum tubes without additives).
    EDTA Plasma: At least 0.5 mL blood plasma (EDTA tubes).
    CSF: At least 0.5 mL CSF (polypropylene tubes).

  3. Send samples and request form

    Within Sweden
    Samples can be sent at room temperature to:
    Envelopes and smaller boxes:
    Wieslab AB, Box 50117, 20211 Malmö, Sweden

    Larger boxes and frozen samples:
    Wieslab AB, Lundavägen 151, 21224 Malmö, Sweden

    International
    Samples can be sent at room temperature to:
    Wieslab AB, Lundavägen 151, 21224 Malmö, Sweden

Last updated: 2026-08-27