MUSC expert says new Alzheimer's blood test comes at a tipping point

A new blood test for Alzheimer’s disease, Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, will help determine if people have that type of dementia. There’s a lot of interest in knowing about the presence of Alzheimer’s before the progressive condition takes a devastating toll. A recent report by the Alzheimer’s Association found most people it surveyed want a simple test that could lead to early access to treatment.

This test is not, at this point, for people who want to know if they’ll develop the disease in the future. It’s for people 55 and up who are already showing possible signs of Alzheimer’s. But it could still have a big impact. An estimated 10% of people age 65 and older have the disease. And knowing their diagnosis could help ensure they get the right care for their condition. 

It could also give them access to new treatments for Alzheimer’s, according to Steven Carroll, a professor in the College of Medicine at the Medical University of South Carolina, director of the South Carolina Alzheimer’s Disease Research Center and leader of MUSC’s brain bank, a donation center to support research. 

“We have some treatments for Alzheimer’s now. In particular, Leqembi has been getting a lot of attention.” Research suggests that Leqembi helps people with Alzheimer’s remember things, solve problems and complete daily tasks for longer than if they weren’t getting the drug.

 

“I think tipping point is probably a good term for what we’re seeing. We are now beginning to be able to have some ways to intervene,” Carroll said.

The newest way, the Lumipulse test, measures levels of tau and beta-amyloid. “It's looking at the ratio of two proteins that we know are altered and accumulated abnormally in Alzheimer's disease,” Carroll said. 

The Food and Drug Administration said a multi-center study of about 500 people found the blood test could reliably find amyloid pathology linked to Alzheimer’s disease in patients with cognitive impairment.

But Lumipulse shouldn’t be used as the sole source of an Alzheimer’s diagnosis, Carroll said. “You get your best accuracy when you combine a thorough mental and physical examination with the test. But it's an important step forward.”

Biomarkers, signs of health conditions you can find through methods such as blood tests, have been what Carroll called the holy grail for people in the field of Alzheimer’s disease research and treatment. 

“Now, we know that the earlier that we can pick these up, the greater chance you have to actually do something about it. As someone said to me last night, this is going to become something where we'll be able to convert what was a death sentence into a manageable chronic disease.”

For that to happen, the work needs to continue, Carroll said. “We still need better biomarkers that could be accurate earlier in the disease. We also need biomarkers that will pick up some of these other conditions that may be coexisting in the brain together with Alzheimer's. We know that things like Lewy body disease and the frontotemporal dementias are actually reasonably common.”

He hopes to find some of those biomarkers through the use of two machines called Quanterix analyzers he has access to through his work with MUSC and the South Carolina Alzheimer’s Disease Research Center.

He also hopes the use of Lumipulse expands beyond the current pool of people who qualify. “I think they're really trying to make sure the tests are available for the people who can really benefit from them. The problem is with everything in medical care, you know, you don't have infinite resources. I'm sure these things will get scaled up,” Carroll said, referring to a wider rollout.