Alzheimer’s blood test predicts the disease with 94% accuracy

New Alzheimer’s blood test is 94% accurate at predicting the devastating brain disease up to 20 years before memory loss begins, study claims

  • In tests on 158 people over 50, most of which had normal cognition, scientists found a blood test combined with genetic testing was 94% accurate 
  • They think it could predict the disease 20 years before symptoms start
  • Early diagnosis could help slow down Alzheimer’s progression and may even be the key to finding a more effective drug or cure 

Scientists have developed a blood test that can detect Alzheimer’s proteins that build up in the brain up to 20 years before symptoms of the disease appear, a new study reveals. 

The test, created by researchers at Washington University St Louis, boasts 94 percent accuracy at predicting the devastating brain disease, they report. 

Alzheimer’s has no cure, and the only approved treatment so far only helps to slow down disease’s progression if it’s given early on. 

So a blood test that can diagnose the disease decades before memory loss begins might help give people years of quality life back that they would otherwise have lost. 

A new blood test for Alzheimer’s disease can detect the disease with 94 percent accuracy up to 20 years ahead of when symptoms appear, a new study suggests 

On average, Alzheimer’s sufferers only live four to eight years after diagnosis. 

During that time, decline may be a slow and steady plod that drags on or it may happen suddenly – a dramatic plunge into confusion, dependence, isolation and fear. 

For whatever number of years a person lives with Alzheimer’s, there are seven stages to the disease, ranging from no clinical impairment to very severe cognitive decline. 

People are commonly diagnosed during the disease’s third stage, which is marked by mild cognitive decline that becomes apparent to people who have long known the person, such as family members and primary care physicians. 

If the disease is caught in its mild to moderate stages, there area handful of drugs that can help slow down the progressive loss of memory and reduce behavioral changes like agitation. 

But past these earlier stages, there’s little that can be done for the mind. 

Instead, medications for moderate to severe Alzheimer’s mostly make patients easier to care for, preserving the mot basic functions – such as using the bathroom on their own – but often only for mere months. 

This year alone, the National Institutes of Health (NIH) are expected to spend $2.3 billion on Alzheimer’s research of all kinds. Much of this budget will go to moonshot studies in search of a cure. 

But until one is found, early diagnosis is the only hope to give tens of millions of Alzheimer’s sufferers a better quality of life for a little longer.

Currently, most people are diagnosed with Alzheimer’s using a subjective test. 

PET scans for amyloid bet plaques and spinal taps to analyze blood plasma from the spinal cord fluid provide better measures, but are astronomically expensive and, in the case of spinal taps, very painful.  

What’s more, at least a dozen trials of Alzheimer’s drugs have failed, and ‘it might not be because the drugs don’t work, kind of paradoxically,’ says co-author of the new study, Dr Suzanne Schindler, told

‘We think that amyloid is what initiates and is necessary to cause Alzheimer’s, but it’s not sufficient [on its own]. 

‘If we can target its accumulation early on we may be able to prevent the disease but the bprog is a lot of these trials started giving the medication late in the course of the disease when a you already have a lot of damage and other processes going that are pretty impossible to top.’ 

The blood test Dr Schindler and her team are developing would be far cheaper and, their latest tests in 158 cognitively normal people over 50 suggest, could detect Alzheimer’s far earlier. 

On its own, the blood test matched the PET scan of plaques in the same person’s brain 88 percent of the time, according to the study, published in the journal Neurology. 

Once the researchers took into account the results of genetic tests for Alzheimer’s risks, that accuracy went up to 94 percent. 

There were some false positives in those initial scan-DNA test comparisons – but what first appeared to be faults in the tests later proved evidence of their unprecedented accuracy. 

When these subjects were given brain scans an average of four years later, those former false-positive subjects also had positive signs of Alzheimer’s in their brain scans.  

 The scientists anticipate that their test could forecast Alzheimer’s disease as much as 20 years in the future. 

Dr Schindler is hopeful that the availability of a cheaper test for earlier detection of Alzheimer’s plaques ‘will speed up the process so we can find an effective drug faster.’ 

And that will translate to these future drugs’ efficacy for patients, too. 

‘The value of the test is in identifying people very early in the course of the disease…and essentially clear out amyloid, and those people theoretically would not go on to develop dementia,’ Dr Schindler says. 

‘Of course this has to be proven, but we think it might work.  

‘But to do this, you have to have a good test.’      

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