Blood test detects Alzheimer's before onset of symptoms

Alzheimer's disease could be diagnosed by using a simple blood test, long before the onset of symptoms.

Research co-author Nicolas Ashton told CGTN Europe that his team tested volunteers' blood for a key biomarker of the disease, called p-tau217, which increases at the same time as other damaging proteins - beta amyloid and tau - build up in the brains of people with the disease.  

The test, published in the medical journal JAMA neurology on Monday, was up to 97 percent accurate in detecting tau and 96 percent in identifying elevated levels of beta amyloid. Patients in the U.S. and Sweden who underwent the tests showed little or no cognitive decline before their blood was drawn.

Asshton, Associate Professor at the University of Gothenburg, explained: "We've actually known for years that the potential of a blood test to diagnose Alzheimer's disease was a real possibility. So the results that we presented in the study to us are not really that much of a surprise."

READ MORE

Germany ends ban on dual nationality, makes it easier to get citizenship

RAZOR: A conversation with Carlo Rovelli

EU adopts sanctions against six entities involved in Sudan conflict

He added: "The big difference is that now we've moved this blood test from a research setting to something that can be used in a healthcare environment. We have independently tested this with a company called ALZ Path and we've independently tested it as a laboratory. We can show that it's very high performing in detecting Alzheimer's disease." 

Currently, Alzheimer's - the most common form of dementia and causes progressive memory loss and cognitive impairment - can only be diagnosed by carrying out a lumbar puncture, advanced brain imaging scans or a spinal tap in the back. Most patients don't have access to these treatments, leaving clinicians to diagnose based on the presentation of symptoms. But that could be about to change.

"This blood test offers a biological interpretation of the disease to everyone," says Ashton. "This is something that everyone can access because it's so easy to collect blood. That means that people can have a better diagnosis. Not just a guess. Not just an opinion. It will be a definitive diagnosis."

An early and definitive diagnosis could transform the management of the disease and the long term health of sufferers, if it's combined with new treatments.

"Recently, two drugs in the U.S. (Aducanumab and Leqembi) were approved for the treatment of Alzheimer's," says Ashton. "What these drugs does is it goes into the brain. It binds a protein called amyloid and it clears it. And this is undisputed. 

"The benefit to the patients seems to be quite mild, but the progress is really advancing. These drugs work so much better if you diagnose someone earlier. This blood test is going to have important ramifications because people will be able to access it earlier and hopefully, in the future, start using the drug which will help them to stave off the disease." 

The next phase of research for Ashton is identifying similar types of tests for different types of dementia. "Alzheimer's disease is only representative of 60 percent of the dementia cases that we diagnose - the other 40 percent we don't really have similar tests for at the moment. And that's our big next big challenge." 

Subscribe to Storyboard: A weekly newsletter bringing you the best of CGTN every Friday