New Blood Test Detects Alzheimer’s Earlier by Analyzing Protein Structure

A subtle shift in the shape of proteins in the blood, rather than their quantity, may offer a new way to detect and track Alzheimer’s disease, according to research published in Nature Aging in February 2026. The findings, stemming from work at Scripps Research, suggest that structural changes in certain circulating proteins can distinguish between cognitively normal individuals, those with mild cognitive impairment (MCI), and patients diagnosed with Alzheimer’s with a high degree of accuracy. This approach could potentially move diagnosis and intervention to an earlier stage of the disease, before significant neurological damage occurs.

Beyond Amyloid and Tau: A New Lens on Alzheimer’s

For decades, Alzheimer’s disease has been primarily understood through the lens of amyloid plaques and tau tangles – abnormal protein deposits that accumulate in the brain. Current diagnostic tests often focus on measuring the levels of amyloid beta (Aβ) and phosphorylated tau (p-tau) in blood or spinal fluid. However, these biomarkers don’t always capture the earliest biological changes associated with the disease. As the Alzheimer’s Association reports, an estimated 7.2 million Americans age 65 and older are currently living with Alzheimer’s, highlighting the urgent demand for more sensitive and earlier detection methods.

The Scripps Research team, led by Professor John Yates, took a different tack. They hypothesized that changes in protein structure – how proteins fold and interact – might be more sensitive indicators of early disease progression. “Many neurodegenerative diseases are driven by changes in protein structure,” Yates explained. “The question was, are there structural changes in specific proteins that might be useful as predictive markers?”

Proteostasis and the Unfolding Story of Alzheimer’s

The research builds on a growing understanding of “proteostasis” – the cellular system responsible for maintaining protein health, ensuring they fold correctly and removing damaged ones. As we age, this system becomes less efficient, increasing the likelihood of misfolded proteins. Scientists now believe that a breakdown in proteostasis isn’t just a consequence of Alzheimer’s, but may be a key driver of the disease. If proteostasis is disrupted in the brain, the researchers reasoned, similar structural changes might also be detectable in proteins circulating in the bloodstream.

Analyzing Protein Structure with Mass Spectrometry

To test this hypothesis, the team analyzed plasma samples from 520 participants, categorized into three groups: cognitively normal adults, individuals with MCI, and those with a confirmed Alzheimer’s diagnosis. They employed a technique called mass spectrometry to map the structural landscape of the proteins, specifically looking at how exposed or buried certain locations within the proteins were – indicators of changes in their overall shape. This data was then fed into machine learning algorithms to identify patterns associated with different stages of the disease. SciTechDaily provides a helpful overview of this process.

The results were striking. As Alzheimer’s progressed, certain blood proteins appeared to become less structurally “open.” These structural changes proved to be more informative than simply measuring the concentration of the proteins themselves.

Three Proteins Stand Out

Among the proteins analyzed, three showed the strongest correlation with Alzheimer’s status: C1QA, involved in immune signaling. clusterin, which plays a role in protein folding and amyloid removal; and apolipoprotein B, a protein crucial for transporting fats and maintaining blood vessel health. “The correlation was amazing,” said co-author Casimir Bamberger, a senior scientist at Scripps Research. “It was very surprising to find three lysine sites on three different proteins that correlate so highly with disease state.”

Using changes at specific sites within these three proteins, researchers were able to classify participants with approximately 83% overall accuracy. When comparing two groups directly – for example, healthy individuals versus those with MCI – the accuracy rose to over 93%.

Tracking Progression and Monitoring Treatment Response

The reliability of this three-protein model was further validated through testing on independent participant groups and by analyzing blood samples collected over several months. Repeat tests demonstrated approximately 86% accuracy in identifying disease status and reflected changes in diagnosis over time. Importantly, the structural score also correlated with cognitive test results and, to a lesser extent, with MRI measurements of brain shrinkage.

This suggests that analyzing protein structure in blood could serve as a valuable complement to existing amyloid and tau tests. Because it focuses on structural changes linked to the underlying biology of the disease, it may offer a more nuanced understanding of disease stages, track progression, and potentially evaluate the effectiveness of treatments.

What’s Next: Validation and Expansion

While these findings are promising, Professor Yates emphasizes the need for larger studies with longer follow-up periods to confirm the results. “Detecting markers of Alzheimer’s early is absolutely critical to developing effective therapeutics,” he stated. “If treatment can start before significant damage has been done, it may be possible to better preserve long-term memory.”

Researchers are also exploring whether this structural profiling method can be applied to other neurodegenerative diseases, such as Parkinson’s, and even to cancer. The potential to identify early biomarkers for a range of conditions by examining protein structure represents a significant step forward in disease detection and treatment. The study, “Structural signature of plasma proteins classifies the status of Alzheimer’s disease,” was supported by grants from the National Institutes of Health (Scripps News).

Further research will focus on refining the protein panel and establishing standardized protocols for clinical implementation. The ultimate goal is to develop a readily available blood test that can be used to identify individuals at risk of Alzheimer’s disease, allowing for earlier intervention and potentially slowing or preventing the progression of this devastating illness.