Blood test predicts Alzheimer’s disease progression years before brain scan changes

• A study suggests that a blood test measuring the biomarker pTau217 can detect early signs of Alzheimer’s disease years before symptoms or signs appear on brain scans.
• Higher pTau217 levels in cognitively healthy adults were linked to faster buildup of amyloid and tau proteins, as well as future cognitive decline.
• Changes in pTau217 often occurred before positive scans, suggesting it may be a more sensitive early detection tool.
• Low pTau217 levels were associated with a lower likelihood of developing significant Alzheimer’s-related brain changes over many years.

Estimates suggest that more than 7 million American adults are living with Alzheimer’s disease. Receiving a timely diagnosis can provide many benefits, such as helping to reduce cognitive and functional decline and allowing an individual to prioritize their health.

At present, diagnosis typically involves a combination of medical history, cognitive tests, neurological exams, and brain imaging. However, growing evidence is highlighting the possible role of certain proteins in diagnosing Alzheimer’s disease.

The accumulation of these proteins can begin years before clinical symptoms and may serve as measurable, specific biomarkers of underlying neuropathology. As such, they may allow for earlier and more accurate diagnosis than current methods.

Now, a study published in Nature Communications, suggests that measuring blood for phosphorylated tau 217 (pTau217) could reveal the earliest signs of disease progression in otherwise healthy older adults.