Evidence map›Paper›PMID 41604609›Full record

ArticleNeurology2026

Diagnostic Performance of the α-Synuclein Seed Amplification Assay for Dementia With Lewy Bodies: A Comparison Across 4 Laboratories.

Rakesh Kumar, Stephanie Gravett, Vesna Jelic, Johannes Lange, Linn Oftedal, Arianna Ciullini, Merve Begüm Bacınoğlu, Chiara Maria Giulia De Luca, Lola Hamied, Catherine Birck and 11 more

Abstract readComparative StudyMulticenter Study
In one paragraph

Article in Neurology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed.

  1. Article
  2. Article
  3. Review
  4. Review
  5. Article
  6. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

21 authors.

Rakesh KumarDepartment of Neurobiology Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Huddinge, Sweden.ORCID 0000-0003-2029-8687
Stephanie GravettDepartment of Neurobiology Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Huddinge, Sweden.
Vesna JelicDepartment of Neurobiology Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Huddinge, Sweden.ORCID 0000-0002-9241-9022
Johannes LangeCentre for Movement Disorders, Stavanger University Hospital, Norway.ORCID 0000-0003-0604-4891
Linn OftedalCentre for Movement Disorders, Stavanger University Hospital, Norway.ORCID 0000-0003-1793-4013
Arianna CiulliniUnit of Laboratory Medicine, Laboratory of Clinical Pathology, IRCCS Neurologic Institute Carlo Besta, Milan, Italy.
Merve Begüm BacınoğluUnit of Laboratory Medicine, Laboratory of Clinical Pathology, IRCCS Neurologic Institute Carlo Besta, Milan, Italy.
Chiara Maria Giulia De LucaDepartment of Neurology 5 - Neuropathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.ORCID 0000-0002-6233-8272
Lola HamiedLaboratory of Biochemistry and Molecular Biology, University Hospital of Strasbourg, Hautepierre Hospital, France.
Catherine BirckPlateforme de Biologie Structurale Intégrée (BSI-FRISBI), CBI-IGBMC, CNRS UMR 7104, Inserm U1258, University of Strasbourg, Illkirch, France.
Frederic BlancUniversity Hospitals of Strasbourg, CM2R (Research and Resources Memory Center), Day Hospitals, Service of Gerontology Mobile-Neuro-Psy-Research, GeRMINED Department, France.ORCID 0000-0002-6714-3247
Patty L HoedeNeurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, the Netherlands.
Afina W LemstraAlzheimer Center, Department of Neurology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, the Netherlands.ORCID 0000-0002-8933-3260
Maria Camila GonzalezCentre for Age-Related Medicine, Stavanger University Hospital, Norway.ORCID 0000-0003-1061-4164
Dag AarslandCentre for Age-Related Medicine, Stavanger University Hospital, Norway.ORCID 0000-0001-6314-216X
Charlotte E TeunissenNeurochemistry Laboratory, Department of Laboratory Medicine, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, the Netherlands.ORCID 0000-0002-4061-0837
Olivier BousigesLaboratory of Biochemistry and Molecular Biology, University Hospital of Strasbourg, Hautepierre Hospital, France.ORCID 0000-0001-6786-3191
Fabio ModaUnit of Laboratory Medicine, Laboratory of Clinical Pathology, IRCCS Neurologic Institute Carlo Besta, Milan, Italy.ORCID 0000-0002-2820-9880
Jodi Maple-GrødemCentre for Movement Disorders, Stavanger University Hospital, Norway.ORCID 0000-0001-7142-0078
Axel AbeleinDepartment of Medicine Huddinge, Karolinska Institutet, Sweden.
Daniel FerreiraDepartment of Neurobiology Care Sciences and Society, Center for Alzheimer Research, Division of Clinical Geriatrics, Karolinska Institutet, Huddinge, Sweden.ORCID 0000-0001-9522-4338

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

BACKGROUND AND

objectivesThe α-synuclein (α-syn) seed amplification assay (SAA) has shown promising results for diagnosing dementia with Lewy bodies (DLB) using CSF samples. A barrier to implementing α-syn SAA clinically is the use of different protocols for the assay. It is unknown how different protocols perform in comparison with each other. We compared the performance of α-syn SAA across 4 laboratories using CSF samples of patients with DLB.

methodsThis was a retrospective cross-sectional study that included data from 4 different European laboratories. We included probable patients with DLB with a positive dopamine transporter (DaT)-SCAN and known amyloid-β status who had mild-to-moderate dementia, along with age-matched and sex-matched controls. The α-syn SAA was run across 4 laboratories using different protocols varying α-syn concentration and plate reader settings. CSF samples were provided by a fifth independent laboratory, which also performed statistical and result analyses.

resultsWe included 20 patients with DLB (mean age 67 ± 6 years, 60% male) and 10 controls (mean age 67 ± 2 years, 70% male). Neuropathologic confirmation was available for 2 patients with DLB. On average, the 4 laboratories achieved 78.8% sensitivity (minimum 55%, maximum 100%), 77.5% specificity (minimum 60%, maximum 100%), and 78.5% accuracy (minimum 57%, maximum 100%) for discriminating DLB from controls, but our findings show that diagnostic performance of SAA varied across laboratories: Lab A achieved 100% sensitivity (CI 84%-100%) and 100% specificity (CI 72%-100%); Lab B achieved 85% sensitivity (CI 64%-95%) and 90% specificity (CI 59%-99%); Lab C achieved 55% sensitivity (CI 34%-74%) and 60% specificity (CI 31%-83%); and Lab D achieved 75% sensitivity (CI 53%-89%) and 60% specificity (CI 31%-83%). In general, SAA results showed numerically lower sensitivity in β-amyloid (Aβ)-positive patients with DLB (70%) compared with Aβ-negative patients with DLB (87.5%) (nonstatistically significant). A fair agreement of SAA results was obtained across the 4 laboratories (average κ = 0.246). DISCUSSION: This study highlights challenges for the reproducibility of α-syn SAA results across different protocols applied by different laboratories. This finding, together with the methodological variability reported across laboratories, may challenge the clinical implementation of the α-syn SAA. This study provides relevant support for initiating harmonization and standardization of SAA protocols to move the field toward the clinical implementation of SAAs for the biomarker-based diagnosis of DLB. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence of variations in the accuracy of CSF α-syn SAA across 4 separate laboratories in distinguishing patients with DLB from healthy controls.

Indexed as

alpha-SynucleinLewy Body DiseaseAgedAged, 80 and overAmyloid beta-PeptidesBiomarkersCross-Sectional StudiesFemaleHumansLaboratoriesMaleMiddle AgedRetrospective StudiesSensitivity and Specificityalpha-SynucleinAmyloid beta-PeptidesBiomarkers

Identifiers

PMID41604609
PMCPMC12857811

What OpenQuestion holds

Textmetadata
LicenceCC BY
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.