Fig. 2: Positive predictive value at different sensitivity thresholds.
From: A blood-based biomarker workflow for optimal tau-PET referral in memory clinic settings
This figure shows the positive predictive value (PPV) of the individual plasma biomarkers at different sensitivity thresholds (90, 95, and 97.5%) for the BioFINDER-2 (left; n = 548) and TRIAD (right; n = 179) cohorts. Here, PPV represents the percentage of true positive tau-PET scans that can be expected among those individuals who are selected for PET scanning via plasma biomarker screening. Conversely, 1 - PPV represents the percentage of individuals who receive a tau-PET scan (due to high risk for tau pathology as predicted by each plasma biomarker) but are expected to actually be negative for tau pathology. The dotted lines represent the tau-PET positivity rate for BioFINDER-2 (37%) and TRIAD (44%), with pTau217 being the only biomarker providing clear increases in relation to the population positivity rates in both cohorts. Source data are provided as a Source Data File. PET positron emission tomography, Aβ amyloid-beta, pTau= phosphorylated tau, NfL neurofilament light, GFAP glial fibrillary acidic protein.
