TOPLINE:

In real-world clinical practice, adding p‑tau217 testing significantly improved diagnostic accuracy and increased neurologists' diagnostic confidence, with marked reclassification seen in mild cognitive impairment and dementia and confidence gains occurred across all cognitive stages.

METHODOLOGY:

• Researchers conducted a prospective observational study to evaluate whether implementing serum p-tau217 testing improves diagnostic accuracy and increases neurologists' diagnostic confidence when assessing individuals (aged at least 50 years) presented with cognitive problems.
• They included 200 consecutive participants (mean age, 72.15 years; 67.0% women) from a tertiary hospital in Spain across two clinical settings — general neurology (n = 52) and a specialised cognitive neurology unit (n = 148) — between 2024 and 2025.
• At the initial visit, neurologists recorded clinical diagnosis (Alzheimer's disease [AD], other neurodegenerative disorder, or non-neurodegenerative disorder) and rated their diagnostic confidence on a 0-10 scale before receiving p-tau217 test results.
• After receiving p‑tau217 test results, they repeated the same assessments for a direct comparison.

TAKEAWAY:

• Overall, 38.5% of participants had subjective cognitive decline, 47.5% had mild cognitive impairment, and 14.0% had dementia. At the initial visit, 46% of participants were diagnosed with AD, 7% were diagnosed with other neurodegenerative disorder, and 47% were diagnosed with non-neurodegenerative disorder.
• After receiving p-tau217 test results, the clinical diagnosis was changed in approximately 25% of participants, and the diagnostic confidence improved significantly from 6.90 ± 1.74 to 8.49 ± 1.68 (t test, -10.46; P < .001).
• Diagnosis was reclassified in mild cognitive impairment (chi square,  47.21) and dementia (chi square, 17.15) groups, and the diagnostic confidence significantly improved across all cognitive stages and in both clinical settings (P < .001 for all).
• Diagnostic agreement with the final diagnosis improved markedly, rising from 75.5% before testing to 94.5% after testing (kappa index, 0.576 vs 0.906).

IN PRACTICE:

"[The study] findings support the clinical utility of p-tau217 from both a biomarker validation and a real-world clinical decision-making perspective, and across all stages of cognitive decline, including subjective cognitive decline," the authors wrote.

SOURCE:

This study was led by Jordi A. Matías‑Guiu, San Carlos Health Research Institute, Hospital Clínico San Carlos, Universidad Complutense de Madrid, Madrid, Spain. It was published online on February 10, 2026, in the Journal of Neurology.

LIMITATIONS:

Only a subset of patients underwent cerebrospinal fluid biomarker analysis as this study was conducted under clinical practice conditions. Since the diagnosis after the initial visit was mainly based on the clinical history and neurologic examination, p-tau217 could complement to a brief clinical assessment. The study used serum rather than plasma.

DISCLOSURES:

This study received partial funding from the Spanish Ministry of Health and Lilly. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.