DIAGNOSTIC TEST 985

Glial Fibrillary Acidic Protein (GFAP)

Diagnostic test for GFAP. For suspicion of CNS damage

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

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.

  2. Prepare your samples

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

  3. Send samples and request form

    Within Sweden
    Send samples frozen 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
    Send samples frozen to:
    Wieslab AB, Lundavägen 151, 21224 Malmö, Sweden

Read our sampling instructions for more information

Last updated: 2025-08-18