Indication
Suspected neuronal damage in the CNS or PNS
Method
SIMOA (single molecule array)
Can be tested in serum, EDTA-plasma or CSF.
Result
The result is reported as ng/L. If urgent NfL-testing is required, please contact the laboratory at +46 40 53 76 60.
Reference interval (serum/EDTA-plasma):
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 |
There are several benefits of measuring NfL in serum/plasma rather than in CSF:
Interpretation
Neurofilaments are parts of the cytoskeletal structure of neurons and are abundantly found in axons. They are important for maintaining size and providing structural support for the neuron. There are currently five known neurofilament proteins that can co-assemble in different combinations. Neurofilament light (NfL) is the most commonly used biomarker.
During axonal damage in the CNS, NfL leaks into CSF and can often also be detected in serum and plasma. Levels of NfL in serum and plasma are several times lower than in CSF, but the correlation is high – and they can be used as a marker of neuronal damage in both CNS and PNS. Analysis in plasma results in approximately 10% lower NfL levels than in serum.
NfL is a general marker of neuronal damage – it does not say anything about the underlying cause. Significantly elevated levels indicate widespread diffuse axonal damage and can be seen in several conditions, including encephalitis. High levels can also be seen in ALS with upper motor neuron damage.
NfL levels in blood can also be used for monitoring neuronal damage. Since the level of NfL varies between individuals and increases with age, the reference intervals are wide and age-related. We therefore recommend that a sample is taken when the disease is well controlled – with no signs of active inflammation in the last three months. This baseline value can be used as the individual's own reference, with a difference of >20% between samples being defined to be significant.
In dementia, mildly elevated CSF levels are usually seen, with slightly higher levels in frontotemporal and vascular dementia compared to Alzheimer's disease. However, there is limited data on NfL in serum and plasma in these groups.
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
Indikation
Misstänkt neuronskada i CNS eller PNS
Metod
SIMOA (single molecule array)
Analys kan utföras i serum, EDTA-plasma eller likvor (Csv).
Svar
Resultat rapporteras som ng/L. Vid behov av akut NfL-analys, kontakta laboratoriet på 040- 53 76 60.
Referensintervall (serum/EDTA-plasma):
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 |
Det finns flera fördelar med att mäta NfL i serum/plasma i stället för i likvor (Csf):
Tolkning
Referenser