# Comparing the Clinical Utility and Diagnostic Performance of CSF P-Tau181, P-Tau217, and P-Tau231 Assays

Article · Leuzy A, Janelidze S, Mattsson-Carlgren N, Palmqvist S, Jacobs D, Cicognola C, Stomrud E, Vanmechelen E, Dage JL, Hansson O

- Archive id: doi:10.1212/wnl.0000000000012727
- Published: 2021-09-07
- Venue: Neurology
- DOI: https://doi.org/10.1212/wnl.0000000000012727
- PMID: 34493616
- PMCID: PMC8605616
- Citations: 104
- Source URL: https://doi.org/10.1212/wnl.0000000000012727
- PDF: https://europepmc.org/articles/PMC8605616/pdf
- Provenance: europepmc

## Abstract

Background and objectives Phosphorylated tau (p-tau) in CSF is considered an important biomarker in Alzheimer disease (AD) and has been incorporated in recent diagnostic criteria. Several variants exist, including p-tau at threonines 181 (p-tau181), 217 (p-tau217), and 231 (p-tau231). However, no studies have compared their diagnostic performance or association to β-amyloid (Aβ) and tau-PET. Understanding which p-tau variant to use remains an important yet answered question. We aimed to compare the diagnostic accuracy of p-tau181, p-tau217, and p-tau231 in CSF for AD and their association with Aβ and tau-PET. Methods A total of 629 participants in the Swedish BioFINDER-2 study were included (cognitively unimpaired, n = 334; Aβ-positive mild cognitive impairment, n = 84; AD dementia, n = 119; and non-AD disorders, n = 92). In addition to p-tau181 and p-tau217 measured using assays with the same detector antibodies from Eli Lilly (p-tau181 Lilly , p-tau217 Lilly ) and p-tau231, we also included p-tau181 measurements from 2 commonly used assays (Innotest and Elecsys). Results Although all p-tau variants increased across the AD continuum, p-tau217 Lilly showed the greatest dynamic range (13-fold increase vs 1.9-5.4-fold increase for other p-tau variants for AD dementia vs non-AD). P-Tau217 Lilly showed stronger correlations with Aβ- and tau-PET ( p \< 0.0001). P-Tau217 Lilly exhibited higher accuracy than other p-tau variants for separating AD dementia from non-AD (area under the curve \[AUC\], 0.98 vs 0.88 \[ p \< 0.0001\] - 0.96 \[ p \< 0.05\]) and for identifying Aβ-PET (AUC, 0.86 vs 0.74 \[ p \< 0.0001\] and 0.83 \[ p \< 0.001\]) and tau-PET positivity (AUC, 0.94 vs 0.80-0.92, p \< 0.0001). Finally, p-Tau181 Lilly generally performed better than the other p-tau181 assays (e.g., AD dementia vs non-AD, AUC, 0.96 vs 0.88 \[p-tau181 Innotest \] and 0.89 \[p-tau181 Elecsys \]; p \< 0.0001). Discussion CSF p-tau217 Lilly seems to be more useful than other included p-tau assays in the workup of AD. Varied results across p-tau181 assays highlights the importance of anti-tau antibodies for biomarker performance. Classification of evidence This study provides Class II evidence that p-tau217 provides higher diagnostic accuracy for diagnosis of AD dementia than p-tau181 or p-tau231.

_Abstract reproduced under CC-BY (article license as recorded by Europe PMC; abstract reproduced unmodified apart from markup removal)._

Topics: [Alzheimer's, Parkinson's & Neurodegeneration](https://space-kitty.com/topics/neurodegeneration)

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