Post Content Participants with higher pTau217 levels showed faster Alzheimer’s-related changes, even before clear signs appeared on brain scans. (Photo credit: FreePik)
A simple blood test may soon change how early Alzheimer’s disease is detected. In a new study from Mass General Brigham, published in Nature Communications, researchers found that measuring a protein called plasma phosphorylated tau 217 (pTau217) can reveal early disease-related changes, sometimes even before they show up on conventional brain scans, opening a window to identify risk years in advance.
The study tracked 317 cognitively healthy adults aged 50 to 90 over an average of eight years, analysing their blood markers, brain scans, and cognitive changes. It found that individuals with higher pTau217 levels were more likely to show faster progression of Alzheimer’s-related changes, in some cases even before clear abnormalities appeared on brain scans.
“We used to think that PET scan detection was the earliest sign of Alzheimer’s disease progression, revealing amyloid accumulation in the brain 10 to 20 years before symptoms appear,”said lead author Dr. Hyun-Sik Yang, a neurologist at Harvard Medical School and Mass General Brigham.
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“But now we are seeing that pTau217 can be detected years earlier, well before clear abnormalities appear on amyloid PET scans”, he added.
Alzheimer’s currently has no cure. Every treatment strategy being developed worldwide depends on catching the disease early enough to intervene, before neurons start dying, before memory starts slipping, before families start losing people.
A cheap, accessible blood test that buys back a decade of warning time is not just a scientific result. It is potentially a lifeline.
“As the field is evolving quickly, we’re excited to see discoveries on the research side being rapidly translated to clinical application,” said co-senior author Dr. Jasmeer Chhatwal, a neurologist at Mass General Brigham.
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That gap between discovery and application is where the real story lies, especially in India.
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In 2025, the US Food and Drug Administration cleared a blood-based test for Alzheimer’s disease, signalling a shift toward diagnostics that are less invasive than PET scans or spinal fluid tests. However, regulatory clearance in one country does not automatically translate into access elsewhere.
India already carries a substantial dementia burden, with an ageing population and a healthcare system where specialist neurology care remains concentrated in urban centres, often limiting access for those outside them.
(This article has been curated by Paramita Datta, who is an intern with The Indian Express)
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