Alzheimer’s disease affects millions of older adults in the United States. Most doctors look at two proteins called amyloid beta and phosphorylated tau to decide if someone has the disease. Those tests help, but they do not always show the earliest changes.
What the new test measures
Scientists at Scripps Research created a blood test that does something different. Instead of counting how much protein is in the blood, the test looks at how the proteins are folded. A protein’s shape can change when it is damaged or when the body’s cleaning system, called proteostasis, stops working well.
Why protein folding matters
When we get older, the body’s ability to keep proteins folded correctly gets weaker. Badly folded proteins can cause trouble in the brain and may show up in the blood. The researchers thought that if the brain’s proteins are mis‑folded, some blood proteins might look the same.
How the study was done
The team examined blood from 520 people. They split the participants into three groups: people with normal thinking, people with mild cognitive impairment (MCI), and people diagnosed with Alzheimer’s.
Using a tool called mass spectrometry, they measured which parts of each protein were exposed on the surface and which were hidden inside. Those clues tell us how the protein is folded. Then they used computer learning to find patterns that matched the disease stage.
Three key proteins
Out of many proteins, three gave the strongest clues:
- C1QA – helps the immune system talk to other cells.
- Clusterin – assists in folding proteins and cleaning up amyloid plaques.
- Apolipoprotein B – moves fats in the blood and supports blood‑vessel health.
When the scientists looked at specific spots on these three proteins, they could tell who was healthy, who had MCI, and who had Alzheimer’s with about 83% overall accuracy. Comparing just healthy people to those with MCI pushed accuracy above 93%.
Can the test track disease over time?
The same three‑protein panel worked well in separate groups of participants and in blood drawn months later. Re‑testing the same people after a few months still gave about 86% accuracy and matched changes in memory test scores and brain scans.
What this means for the future
Looking at protein shapes in blood could add useful information to the current amyloid and tau tests. Because it reflects the biology behind the disease, it might help doctors spot early stages, watch how the disease moves forward, and see if medicines are working.
“Finding markers early is crucial for making treatments work,” says one of the lead researchers. “If we can start therapy before big damage happens, we might keep memory stronger for longer.”
Before doctors can use this test, bigger studies over longer periods are needed. The researchers also want to see if the same approach can help detect other illnesses like Parkinson’s or even some cancers.
Funding came from the National Institutes of Health.