INDIVIDUAL TEST 985
Glial fibrillary acidic protein (GFAP)
Indication
Suspicion of CNS damage
Sample material
Serum
- Minim. volume: 0,5 mL
CSF
- Minim. volume: 0,5 mL
Transport
Serum
- Within Sweden: frozen
- International: frozen
CSF
- Within Sweden: frozen
- International: frozen
Method
Single Molecule Array (SIMOA)
Reference interval
SERUM
| Age group | Reference interval |
| 18-60 years | 20-180 ng/L (median 70), based on sera from 92 healthy individuals |
| >60 years | 40-260 ng/L (median 100), based on sera from 30 healthy individuals |
CSF
| Age group | Reference interval |
| 18-60 years | 3900-17700 ng/L (median 8200), based on CSF from 36 individuals without GFAp-related disorders |
| >60 years | 6100-34600 ng/L (median 17800), based on CSF from 16 individuals without GFAp-related disorders |
Result
Results are reported as a concentration in ng/L.
Interpretation
Glial fibrillary acidic protein (GFAP) is a protein primarily found in astrocytes of the central nervous system (CNS) and is crucial for cellular stability and function. GFAP expression increases with astrocyte activation and is released into the cerebrospinal fluid (CSF) following tissue damage. GFAP can cross the blood-brain barrier (BBB) into the bloodstream, and its blood levels can be used to monitor CNS injury. After a single trauma, the highest levels have been observed approximately 20 hours post-injury. Although small amounts of GFAP may also be present in the peripheral nervous system, blood GFAP can serve as a non-specific marker to reflect the extent and severity of CNS injuries. Serum GFAP levels have been shown to be valuable in cases of traumatic brain injury (TBI), stroke, and certain neurodegenerative and neuroinflammatory conditions.
In a study involving 2,800 patients with mild TBI, GFAP levels correlated with medical care needs and were more sensitive than radiological findings in assessing injury extent. In the diagnosis of neuroinflammatory conditions, GFAP levels in CSF can be useful for differentiating between multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD), which can initially be clinically difficult to distinguish. Additionally, in MS, GFAP levels in later stages appear valuable for assessing manifest disease or the risk of developing a progressive form. A challenge in establishing normal reference values is the significant inter-individual variation, even in seemingly healthy individuals, and the fact that higher levels are typically observed with increasing age.
Markedly elevated GFAP levels in CSF are characteristic of active NMO with aquaporin-4 antibodies, especially in longitudinally extensive myelitis, where astrocytes are attacked and destroyed by complement-activating antibodies.
References
- Abdelhak A et al. Nat Rev Neurol. 2022. Blood GFAP as an emerging biomarker in brain and spinal cord disorders. PMID: 35115728
- Kim H et al. Front Neurol. 2022. Glial Fibrillary Acidic Protein in Blood as a Disease Biomarker of Neuromyelitis Optica Spectrum Disorders. PMID: 35370870
- Abdelhak A et al. Sci Rep. 2018. Serum GFAP as a biomarker for disease severity in multiple sclerosis. PMID: 30287870
- Huebschmann NA et al. Front Neurol. 2020. Comparing Glial Fibrillary Acidic Protein (GFAP) in Serum and Plasma Following Mild Traumatic Brain Injury in Older Adults. PMID: 33071938
- Sun M et al. Mult Scler Relat Disord. 2021. A candidate biomarker of glial fibrillary acidic protein in CSF and blood in differentiating multiple sclerosis and its subtypes: A systematic review and meta-analysis. PMID: 33819724
- Ferrari F et al. J Cereb Blood Flow Metab. 2023. Quantification and prospective evaluation of serum NfL and GFAP as blood-derived biomarkers of outcome in acute ischemic stroke patients. PMID: 37113060
Last updated: 2025-03-18
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ENSKILD ANALYS 985
Glial fibrillary acidic protein (GFAP)
Indikation
Misstanke om CNS skada
Provmaterial
Serum
- Minim. volym: 0,5 mL
Likvor
- Minim. volym: 0,5 mL
Transport
Serum
- Inom Sverige: fryst
- Internationellt: fryst
Likvor
- Inom Sverige: fryst
- Internationellt: fryst
Metod
Single Molecule Array (SIMOA)
Referensintervall
SERUM
| Åldersgrupp | Referensintervall |
| 18-60 år | 20-180 ng/L (median 70), baserat på sera från 92 friska individer |
| >60 år | 40-260 ng/L (median 100), baserat på sera från 30 friska individer |
CSF
| Åldersgrupp | Referensintervall |
| 18-60 år | 3900-17700 ng/L (median 8200), baserat på CSF från 36 individer utan GFAp-relaterade sjukdomar |
| >60 år | 6100-34600 ng/L (median 17800), baserat på CSF från 16 individer utan GFAp-relaterade sjukdomar |
Resultat
Resultat anges som koncentration i ng/L.
Tolkning
Glialfibrillärt surt protein (GFAP) är ett protein som framför allt finns i astrocyter i centrala nervsystemet (CNS) och är viktigt för cellernas stabilitet och funktion. Uttrycket av GFAP ökar vid astrocytaktivering och frisätts i cerebrospinalvätska (CSF) vid vävnadsskada. GFAP kan passera över BBB till blodet och nivån i blod kan användas för att monitorera skada i CNS. Efter engångstrauma har högsta nivån setts efter cirka 20 timmar. Även om en mindre del GFAP även kan finnas i perifera nervsystemet kan GFAP i blod användas som en ospecifik markör för att spegla utbredning och grad av skador i CNS. Nivån av GFAP i serum har visat sig vara av värde vid såväl traumatisk hjärnskada (TBI) som stroke, vissa neurodegenerativa och neuroinflammatoriska tillstånd.
I en studie med 2 800 patienter med mild TBI korrelerade GFAP-nivå med det medicinska vårdbehovet och var känsligare än radiologiska fynd för bedömning av skadeutbredning. Vid diagnostik av neuroinflammatoriska tillstånd kan nivån av GFAP i likvor vara av värde för att differentiera mellan multipel skleros (MS) och neuromyelitis optika spektrum sjukdom (NMOSD) som initialt kan vara svåra att åtskilja kliniskt. Vid MS verkar GFAP-nivåerna i senare skede dessutom vara av värde för bedömning av manifest eller risk att utveckla progressiv sjukdom. Ett problem för att fastställa normalvärden är att den interindividuella variationen är stor även hos till synes friska och högre nivåer ses normalt med stigande ålder.
Kraftigt förhöjda nivåer av GFAP i likvor är typiskt vid aktiv NMO med antikroppar mot aquaporin-4, framför allt vid långsträckta myeliter, där astrocyter attackeras och destrueras av de komplementaktiverande antikropparna.
Referenser
- Abdelhak A et al. Nat Rev Neurol. 2022. Blood GFAP as an emerging biomarker in brain and spinal cord disorders. PMID: 35115728
- Kim H et al. Front Neurol. 2022. Glial Fibrillary Acidic Protein in Blood as a Disease Biomarker of Neuromyelitis Optica Spectrum Disorders. PMID: 35370870
- Abdelhak A et al. Sci Rep. 2018. Serum GFAP as a biomarker for disease severity in multiple sclerosis. PMID: 30287870
- Huebschmann NA et al. Front Neurol. 2020. Comparing Glial Fibrillary Acidic Protein (GFAP) in Serum and Plasma Following Mild Traumatic Brain Injury in Older Adults. PMID: 33071938
- Sun M et al. Mult Scler Relat Disord. 2021. A candidate biomarker of glial fibrillary acidic protein in CSF and blood in differentiating multiple sclerosis and its subtypes: A systematic review and meta-analysis. PMID: 33819724
- Ferrari F et al. J Cereb Blood Flow Metab. 2023. Quantification and prospective evaluation of serum NfL and GFAP as blood-derived biomarkers of outcome in acute ischemic stroke patients. PMID: 37113060
Senast uppdaterat: 2025-03-18