A blood test may detect Alzheimer's before symptoms show


The blood test will make it easier to diagnose patients with the degenerative disease

If you are concerned that you might be at risk of Alzheimer's disease, a blood test might answer a lot of questions. A new study published in JAMA Neurology explored the efficacy of a new blood test that scientists say can detect Alzheimer's

The goal of the blood test is to identify key markers of Alzheimer’s – p-tau217, a biomarker of the disease, as well as beta-amyloid and tau, two proteins that are elevated with Alzheimer’s

Ultimately, the blood test proved to be effective. It showed that higher levels of beta-amyloid and tau in the blood were also linked with higher levels of the p-tau217 biomarker. 

A look into the study

The researchers had nearly 800 participants involved in the study, pulling data from three research cohorts – the Translational Biomarkers in and Aging and Dementia (TRIAD) cohort, the Wisconsin Registry for Alzheimer’s Prevention, and the Sant Pau Initiative on Neurodegeneration (SPIN). 

In addition to the blood test, which came from the company ALZpath, participants were also tested for Alzheimer’s using the current methods – spinal tap and brain scan. The researchers then analyzed data over the course of five months. 

The blood test proved to be overwhelmingly effective at identifying patients with Alzheimer’s. Overall, the test was 97% accurate in identifying elevated levels of tau, and 96% effective at identifying elevated levels of beta amyloid. 

Among all of the participants, just 20% had results that would require further clinical testing. This means that the test showed clear, accurate results in 80% of the participants involved in the study. 

These findings are also important because not all of the participants were showing signs of cognitive decline over the course of the study, though their blood tests indicated elevated levels of the two Alzheimer’s-related proteins. This means that the blood test was effective at identifying Alzheimer’s before symptoms are showing up. 

Making tests more available

Another key point of this study is that a blood test would make Alzheimer’s detection even more accessible – and much easier to obtain. 

Currently, securing a spinal tap or brain scan to get an Alzheimer’s diagnosis can be difficult for consumers from both a cost and general accessibility standpoint. 

With a blood test, the cost burden goes way down, and accessibility would improve drastically. This would allow more consumers to get tested, more cases to be diagnosed earlier and more accurately, and more patients receiving treatment as quickly as possible. 

“A clinical Alzheimer’s diagnosis often lacks sensitivity and specificity, resulting in many individuals with mild cognitive impairment (40%-60%) or dementia (20%-30%) who exhibit typical Alzheimer’s symptoms lacking beta amyloid pathology,” the researchers wrote

“In primary care, it is estimated that more than 50% of patients with cognitive impairment remain undiagnosed or incorrectly diagnosed because of the lack of accessible and cost-effective tools. Thus, blood biomarkers are set to revolutionize clinical care by providing objective biomarker-based information.” 

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