New blood test that can spot Alzheimer’s offers diagnosis hope

At the moment we can only ­detect Alzheimer’s once the destructive protein plaques are already formed in the brain. Too late.

Any treatments we have are largely ineffective at this stage.

We know, however, the first changes of Alzheimer’s happen up to 20 years earlier.

But breakthrough ­research in ­Germany has forged a new test that could detect the disease at a much earlier stage than at present.

“This has paved the way for early stage therapy approaches, where the as yet inefficient drugs on which we had pinned our hopes may prove ­effective,” says Professor Klaus Gerwert from the Department of Biophysics at RUB University, in Bochum, Germany.

In Alzheimer’s patients, we know the abnormal protein, amyloid, infiltrates the brain long before symptoms arise.

Klaus Gerwert’s team has tracked this process using a simple blood test. It means the disease can be picked 
up approximately eight years before the first signs become obvious.

The test detected almost three-quarters of early ­Alzheimer’s patients, but it also gave troublesome false ­positives.

So the researchers have devised a two-tier diagnostic test.

In step one, they use the original blood test to identify high-risk individuals.

In step two, they add a dementia-specific biomarker, called tau protein, and run further tests on those people who tested positive in step one. If both give a ­positive result, there’s a high likelihood of Alzheimer’s disease.

“Through the combination of both analyses, 87 of 100 Alzheimer’s patients were correctly identified in our study,” summarises Prof Gerwert.

“And we reduced the number of false positive diagnoses in healthy subjects to three out of 100. The second analysis is carried out in cerebrospinal fluid that’s extracted from the spinal cord.

“Now, new clinical studies with test participants in very early stages of the disease can be launched.”

His hope is drugs which failed to improve Alzheimer’s in ­established cases will have an effect in those earlier cases.

He believes the new test “opens up a new therapy window”.

“Once amyloid plaques have formed, it seems that the disease can no longer be treated,” says Dr Andreas Nabers, head of the research group and co-developer of the Alzheimer’s test. “If our attempts to arrest the progression of Alzheimer’s fail, it will put a lot of strain on our society.”

Prof Gerwert added: “We are now conducting in-depth research to detect the second biomarker, namely tau protein, in the blood, in order to supply a solely blood-based test in future.” This is such promising news.