INDIVIDUAL TEST 994

Neurofilament light protein (NfL) – serum/CSF

Indication

Suspected neuronal damage in the CNS or PNS

Method

SIMOA (single molecule array)

Response

The result is reported as ng/L.

Reference interval (serum):

Age

Concentration

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

Reference interval (CSF):

Age

Concentration

<30 years:

<380 ng/L

30-39 years:

<560 ng/L

40-59 years:

<890 ng/L

≥60 years:

<1850 ng/L

 

Interpretation

Neurofilament light protein (NfL, about 68 kD) is a subunit of neurofilament that is an important cytoskeleton in the neuron and is most abundant in myelinated axons. In axonal damage, NfL leaks into CSF and the level reflects the degree of neuronal degeneration. Elevated NfL levels can also be detected in the serum. Serum levels are several times lower than in CSF but the correlation is high. The level of NfL in serum can thus be used as a marker of neuronal degeneration in the CNS.

Elevated levels of NfL are a nonspecific marker of neuronal degeneration and do not tell about the underlying cause. Significantly elevated levels indicate widespread diffuse axonal injury and can be seen at e.g. encephalitis. High levels can also be seen in ALS with upper motor neuron damage.

The level of NfL is of great value in monitoring the course of the disease in demyelinating diseases and is included in the follow-up routine of relapsing multiple sclerosis. In dementia, mildly elevated CSF levels are usually seen with slightly higher levels in frontotemporal and vascular dementia compared to Alzheimer's disease. However, the experience of serum NfL in these disease groups is limited.

References

  1. Disanto, G. et al., Serum Neurofilament light: A biomarker of neuronal damage in multiple sclerosis. Annals of neurology 2017, 81(6), 857–870.
  2. Schott JM, et al., Stability of blood-based biomarkers of Alzheimer's disease over multiple freeze-thaw cycles. Alzheimer’s Dement (Amst). 2018 Jul 2; 10:448-451.
  3. Jens Kuhle et al., Blood neurofilament light chain as a biomarker of MS disease activity and treatment response. Neurology. 2019 Mar 5;92(10)
  4. Hviid CVB et al., Reference interval and preanalytical properties of serum neurofilament light chain in Scandinavian adults. Scand J Clin Lab Invest. 2020 Feb 20:1-5.
  5. Khalil M et al., Serum neurofilament light levels in normal aging and their association with morphologic brain changes. Nat Commun. 2020 Feb 10;11(1):812.

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Neurology

ENSKILD ANALYS 994

Neurofilament light protein (NfL) – serum/likvor (CSF)

Indikation

Misstänkt neuronskada i CNS eller PNS

Metod

SIMOA (single molecule array)

Svar

Resultat rapporteras som ng/L.

Referensintervall (serum):

Ålder

Koncentration

18-40 år:

2.8 – 9.7 ng/L

41-65 år:

4.6 – 21.4 ng/L

>65 år:

7.5 – 53.8 ng/L

Referensintervall (CSF/likvor):

Ålder

Koncentration

<30 år:

<380 ng/L

30-39 år:

<560 ng/L

40-59 år:

<890 ng/L

≥60 år:

<1850 ng/L

 

Tolkning

Neurofilament light protein (NfL, ca 68 kD) utgör en subenhet i neurofilament som är ett viktigt cytoskelett i neuron och förekommer rikligast i myeliniserade axon. Vid axonala skador läcker NfL ut i likvor och nivån avspeglar graden av neuronsönderfall. NfL förhöjda nivåer kan även detekteras i serum. Nivåerna i serum är flerfaldigt lägre än i likvor men korrelationen är hög. Nivån av NfL i serum kan därmed användas som markör för neuronsönderfall i CNS.

Förhöjda nivåer av NfL är en ospecifik markör för neuronalt sönderfall och säger inte något om bakomliggande orsak. Kraftigt förhöjda nivåer talar för utbredd diffus axonal skada och kan ses vid t.ex. encefalit. Höga nivåer kan även ses vid ALS med övre motorneuronskada.

Nivån av NfL har stort värde vid monitorering av sjukdomsförloppet vid demyeliniserande sjukdomar och ingår vid rutinuppföljning av skovvis multipel skleros. Vid demenssjukdomar ses oftast lätt-måttligt förhöjda nivåer i likvor med något högre nivåer vid frontotemporal och vaskulär demens jämfört med Alzheimers sjukdom. Erfarenheten av NfL i serum på dessa sjukdomsgrupper är dock begränsad.

Referenser

  1. Disanto, G. et al., Serum Neurofilament light: A biomarker of neuronal damage in multiple sclerosis. Annals of neurology 2017, 81(6), 857–870.
  2. Schott JM, et al., Stability of blood-based biomarkers of Alzheimer's disease over multiple freeze-thaw cycles. Alzheimer’s Dement (Amst). 2018 Jul 2; 10:448-451.
  3. Jens Kuhle et al., Blood neurofilament light chain as a biomarker of MS disease activity and treatment response. Neurology. 2019 Mar 5;92(10)
  4. Hviid CVB et al., Reference interval and preanalytical properties of serum neurofilament light chain in Scandinavian adults. Scand J Clin Lab Invest. 2020 Feb 20:1-5.
  5. Khalil M et al., Serum neurofilament light levels in normal aging and their association with morphologic brain changes. Nat Commun. 2020 Feb 10;11(1):812.

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