Affordable blood tests detect signs of early Alzheimer’s at a lower cost

Keck researchers’ medical school has developed a blood test that could change the way we get Alzheimer’s disease years before symptoms appear.

The new test, called 5ADCSI (Penta-plex Alzheimer’s disease capture sandwich immunoassay) simultaneously detected five key biomarkers, more than any commercially available blood test, while devices already common in many laboratories are running. This approach greatly reduces costs and has the potential to allow extensive early screening of Alzheimer’s disease with cholesterol testing routines, opening up new possibilities for early intervention when treatment is likely to be most effective.

The proof-of-concept study, recently published in the Journal of Alzheimer’s Disease and funded by the National Institutes of Health, demonstrates how this affordable testing method translates our approach into a disease that has usually developed silently for decades.

How the test works: Detect multiple biomarkers at once

“Our tests are the most cost-effective and relatively easy to implement than other existing technologies, as many laboratories in universities, hospitals and clinics are already using the technology,” said Ebrahim Zandi, Ph.D., associate professor of molecular microbiology and immunology at Keck School of Medicine, who led the study.

Unlike existing expensive and limited range tests, 5ADCSI leverages the widely available XMAP® technology from Luminex. The system uses tiny color-coded beads coated with antibodies that bind to specific Alzheimer’s disease biomarkers in blood samples:

• Two types of amyloid proteins (Aβ40 and Aβ42)
• Phosphorylated tau
• Neurofilament Light Chain (NFL)
• Glial fibrillary acidic protein (GFAP)

When these proteins are present in blood samples, they bind to the beads. The powerful imaging sensor then detects the emitted color, allowing researchers to accurately measure biomarker levels.

Early detection: The key to intervention

The test is particularly promising that it detects the potential of Alzheimer’s at its earliest stages, long before cognitive symptoms appear. But why is early detection so important?

“In the 10 to 20 years of Alzheimer’s development, proteins such as amyloid and Tau are slowly building up,” Zandi explained. “If we have an affordable blood test that can detect these proteins early, we can start intervening before the symptoms begin.”

In their study, the researchers tested blood samples from 63 participants from three groups of participants: 11 patients with Alzheimer’s disease, 17 patients with mild cognitive impairment (a potential pioneer of Alzheimer’s disease) and 35 healthy individuals. As expected, the test detected the highest levels of biomarker in patients with Alzheimer’s, followed by those with mild cognitive impairment.

From laboratory to clinical practice

5ADCSI’s journey begins with practical solutions. Christopher Beam, associate professor of psychology at the USC Dornsife College, School of Arts and Sciences, needs a more affordable way to measure biomarkers of Alzheimer’s disease to study its research on cognitive aging. Zandi’s team provides 5ADCSI for the solution.

To validate their findings, the researchers also tested cerebrospinal fluid samples, which typically contain higher concentrations of Alzheimer’s-related proteins, but are more difficult and expensive to collect. They found a moderately strong correlation between blood and CSF results, suggesting that blood tests are sensitive enough to be detected early.

Researchers are now working to test the accuracy of 5ADCSI in hundreds of patients at different stages of Alzheimer’s disease, bringing it closer to clinical applications.

Perform routine brain health screening

Zandi envisions the future of this technology becoming part of routine health screening worldwide. His team’s long-term goal is to create a comprehensive brain health risk assessment that combines 5ADCSI with genetic testing of APOE4, a genetic variant that is associated with an increase in Alzheimer’s disease.

This approach can transform Alzheimer’s disease from a devastating diagnosis to a manageable condition by intervening early medication and lifestyle modifications (such as increasing exercise, which may slow or prevent cognitive decline).

Given the growing burden of dementia around the world, the affordable nature of the test is particularly important. By relying on technology already widely available, this testing method can democratize access to early Alzheimer’s tests, even outside the United States, in areas with limited advanced healthcare resources.

As researchers continue to refine the technology, it raises an interesting possibility: Will routine brain health assessments end up being as routine as the body of the year? With tools like 5ADCSI, we may be closer to a future before the tool can identify and resolve Alzheimer’s disease.