Researchers from the University of Gothenburg have developed a two-step workflow using a new blood-based p-tau217 biomarker that improves the accuracy of Alzheimer’s Disease (AD) diagnosis. The approach combines plasma p-tau217 with age and the APOE e4 gene to identify high-risk patients in the first step. The second step involves confirmatory testing for those with uncertain outcomes.
The two-step workflow achieves high accuracy with only 6.6% false negatives and 2.3% false positives, providing a clinically useful strategy for AD screening. This approach could significantly reduce the need for more expensive confirmatory tests like cerebrospinal fluid (CSF) or PET scans, resulting in cost savings for society.
The new blood test, called p-tau217, shows promise as an AD biomarker when used in this two-step workflow. It accurately identifies or excludes brain amyloidosis, the most important and earliest pathology of AD. Tau protein, particularly its phosphorylated variant (p-tau), has been extensively researched and developed as a biomarker for AD.
Previous concerns about false positives and false negatives in AD diagnosis prompted the researchers to develop this novel strategy. Misdiagnosis can have ethical and psychological implications, as well as financial and medical risks for individuals who receive unnecessary treatments.
The two-step model was evaluated using plasma p-tau217 in 348 participants with mild cognitive impairment (MCI) from the Swedish BioFINDER studies. It was then validated in the independent TRIAD cohort in Montreal, Canada. At stringent thresholds, the model achieved 97.5% sensitivity and 97.5% specificity, resulting in a low percentage of false negatives and false positives.
The study presents a blood plasma p-tau217-based two-step model for risk stratification of MCI patients into high, low, and intermediate-risk groups for brain amyloidosis and early AD pathology. This model offers high accuracy for identifying high-risk patients, reducing the need for confirmatory CSF or PET testing. It provides a cost-effective strategy for AD screening in memory clinic settings.
The researchers believe that this innovative approach using the p-tau217 blood test has the potential to improve AD diagnosis and reduce the burden on patients, healthcare systems, and society as a whole.
The study was published in the journal Nature Aging.
Original Research: Open access.
“A two-step workflow based on plasma p-tau217 to screen for amyloid β positivity with further confirmatory testing only in uncertain cases” by Kaj Blennow et al. Nature Aging.
About this Alzheimer’s disease research news
Author: Margareta Gustafsson Cubist
Source: University of Gothenburg
Contact: Margareta Gustafsson from Kub – University of Gothenburg
Image: The image is credited to Neuroscience News