Data Sheet 1_Plasma biomarker strategies to reduce diagnostic uncertainty in p-tau217–based assessment of CSF amyloid positivity in secondary-care patients with MCI.docx

We evaluated whether integrating plasma Aβ measurements could reduce diagnostic uncertainty in patients with mild cognitive impairment (MCI).</p>Methods<p>Plasma p-tau217 was measured using the Lumipulse platform, and plasma Aβ40 and Aβ42 were quantified by liquid chromatography-mass spectrometry (ABtest-MS) in 186 secondary-care MCI patients.

CSF Aβ42/Aβ40 defined amyloid status. Logistic regression models were compared, and dual-cutoff strategies targeting 95% predictive values were applied.</p>Results<p>p-tau217 was the strongest individual biomarker. Models incorporating plasma Aβ measures improved AUC, model fit, and reduced the grey zone from 27.4% with p-tau217 alone to 12.3%.