Evidence map›Paper›PMID 42201636›Full record

ArticleNeurology and therapy2026

Inter-assay and Inter-site Performance of Alpha-Synuclein Seed Amplification Assays in Synucleinopathies: A Multicenter 2 × 2 Protocol Comparison.

Roger Plaza-Clar, Maximilian Weber, Vaibhavi Kadam, Christian Deuschle, Yihua Ma, Carly M Farris, Luis Concha-Marambio, David Mengel, Marcello Rossi, Angela Mammana and 4 more

Abstract read
In one paragraph

Article in Neurology and therapy, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing 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

1 citing paper in PubMed.

  1. 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

14 authors.

Roger Plaza-Clar *Department of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany. rogerplazac@gmail.com.ORCID http://orcid.org/0009-0005-1913-3545
Maximilian Weber *Department of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Vaibhavi Kadam *Department of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Christian DeuschleDepartment of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Yihua MaAmprion, San Diego, CA, USA.
Carly M FarrisAmprion, San Diego, CA, USA.
Luis Concha-MarambioAmprion, San Diego, CA, USA.
David MengelDepartment of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Marcello RossiIRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
Angela MammanaIRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
Piero ParchiIRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
Matthis SynofzikDepartment of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Kathrin BrockmannDepartment of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
Thomas GasserDepartment of Neurodegeneration and Hertie-Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.

Funding

Else Kröner-Fresenius-Stiftung; European Union, project European 334 Rare Disease Research Alliance (ERDERA) 101156595Michael J. Fox Foundation for Parkinson's Research 022411Ministero della Salute RF-2021-12374386
6 · The paper itself

Abstract

introductionThe α-synuclein seed amplification assay (synSAA) is a biomarker test for synucleinopathies. Different synSAA conditions have different properties, and some of these conditions enable differentiation between diseases associated with Lewy bodies versus those associated with glial inclusions. Direct cross-assay and inter-site synSAA comparisons evaluating these features remain limited.

methodsTwo synSAA conditions (identified here as sodium phosphate buffer (SPB) and piperazine-N,N'-bis(2-ethanesulfonic acid) (PIPES) SAA conditions) were tested in a controlled 2 × 2 design, each performed at two independent laboratories. Cerebrospinal fluid (CSF) from 60 participants was analyzed, comprising 29 multiple system atrophy (MSA) samples and 31 additional CSF samples including 16 Parkinson's disease/dementia with Lewy bodies (PD/DLB) cases previously screened using SPB-SAA conditions, and 15 neurology ward controls, which were used as analytical controls.

resultsInter-site concordance was high for SPB-SAA (100%) and PIPES-SAA (95%, 0.913 Fleiss' kappa). Compared to clinical diagnosis, sensitivity for detecting synSAA+ MSA cases was 75.0% for PIPES-SAA_A and 81.4% for PIPES-SAA_C, with specificities of 76.9% and 92.3%, respectively. SPB-SAA did not detect MSA at either of the two sites and showed 100% specificity. Inter-assay concordance was high for PD/DLB (88%) and controls (86%), but low for MSA (31%), reflecting the different sensitivity in MSA cases. The overall inter-assay concordance yielded a Fleiss' kappa of 0.23.

conclusionBoth synSAA conditions exhibit high reproducibility and replicability across laboratories yet differ in their diagnostic profiles: PIPES-SAA conditions enable detection of synuclein seeds in MSA, while SPB-SAA conditions showed high specificity for PD/DLB but not detect synuclein seeds in MSA. These findings support context-dependent assay selection and underscore the need for larger multicenter validation of analytical tools intended for clinical use.

Indexed as

Dementia with Lewy bodiesMultiple systems atrophyParkinson’s diseaseSeed amplification assaysSynucleinopathiesα-Synuclein

Identifiers

PMID42201636
PMCPMC13396297

What Socratic holds

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LicenceCC BY-NC
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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 Socratic graph.