Study results published in Alzhemier’s & Dementia demonstrated the diagnostic utility of p-tau217 for differentiating Alzheimer disease (AD) from other neurodegenerative disorders (NDs), including behavioral variant frontotemporal dementia (bvFTD) and primary psychiatric disorders (PDDs). The study also found that neurofilament light chain (NfL) levels helped distinguish AD from PPD with high accuracy, whereas glial fibrillary acidic protein (GFAP) levels did not add diagnostic value.

The study included 341 prospectively recruited participants (between June 2019 and April 2023) from a neuropsychiatry memory clinic who provided a blood sample for biomarker analysis. Researchers analyzed plasma p-tau217, NfL, and GFAP levels in these participants, which included individuals with AD (n=40), bvFTD (n=15), PPD (n=69), as well as a comparator group of control individuals and individuals with NDs.

Key results include the following:

  • Plasma p-tau217 showed strong diagnostic performance for distinguishing AD from bvFTD (96% accuracy) and PPD (93% accuracy).
  • Plasma p-tau217 levels were significantly elevated in individuals with AD compared with bvFTD (standardized boot-strapped GLM with age and sex as additional covariates); β=1.30; 95% CI, 0.71 to 1.73; P<.001) and PPDs (β=1.59; 95% CI, 1.34 to 1.80; P<.001)
  • Plasma NfL levels were elevated in individuals with AD compared with PPD (β=0.87; 95% CI, 0.59 to 1.13; P<.001) but not for individuals with AD compared with bvFTD (β = -0.10; 95% CI, -0.82 to 0.58; P=.788)
  • The plasma NfL/p-tau217 ratio was reduced in individuals with AD compared with bvFTD (β = -1.57; 95% CI, -2.16 to -0.94, P<.001) and PPD (β = -0.99; 95% CI, -0.58 to 1.34; P<.001)
  • GFAP levels were elevated in individuals with AD compared with bvFTD (β=0.80; 95% CI, 0.23 to 1.39; P=.010) and PPD (β=0.82; 95% CI, 0.36 to 1.21, P<.001), but GFAP levels were not elevated in individuals with AD compared with other NDs (P=.108).

Source: Eratne D, Kang M, Malpas CB, et al.  Plasma p-tau217, NfL, GFAP diagnostic performance and biomarker profiles in Alzheimer's disease, frontotemporal dementia, and psychiatric disorders, in a prospective unselected neuropsychiatry memory clinic. Alzheimer's Dement. 2025; 21:e70717.