Revolutionary Alzheimer’s blood test is 94% accurate 20 years before symptoms develop

Revolutionary Alzheimer’s blood test is 94% accurate 20 years before symptoms develop

6th August 2019

Healthcare news (industry news)

A new blood test has been developed that can detect Alzheimer’s-causing proteins in the brain up to two decades before symptoms begin to appear. A study from Washington University St Louis outlines the benefits of the test, which has a 94 per cent accuracy rate.

Early Alzheimer’s diagnosis is vital to combat the condition, because there’s currently no cure, and treatments can delay onset. Most people are not tested for the disease until symptoms, such as memory loss, start to occur and by then the condition already has a hold on the brain.

Early detection could mean many extra years with good quality of life, and the individual retaining their independence for a lot longer. At present, the average life expectancy after Alzheimer’s diagnosis is just four to eight years.

The progression of the disease can vary between cases, with some relatives seeing parents and grandparents slowly deteriorating. In others, the rate at which they become confused, isolated and scared is much more dramatic.

It’s widely accepted that there are seven stages of Alzheimer’s, starting with no clinical impairment right through to very severe cognitive decline. Most diagnoses occur during the third phase of the disease when people who know the patient very well notice changes in their loved one.

Despite scientists all over the world working on a cure for Alzheimer’s, the drugs on the market only slow down memory loss and reduce changes in behaviour, including agitation. Furthermore, these medications are only useful if the condition is detected in its mild to moderate phases.

While PET scans and spinal taps remain effective ways to diagnose Alzheimer’s, they are very expensive and intrusive, causing a lot of pain to the patient. This means a subjective test is usually used, which focuses on a number of questions directed at the individual and it is not up to the level of detail required.

The new blood test, which has been developed by Dr Suzanne Schindler and her team at Washington University St Louis, could be an effective and cheap method of diagnosis. Using the test alone, it matched the PET scan of plaques in the brain 88 per cent of the time, but once genetic tests for Alzheimer’s were taken into account, the accuracy reached 94 per cent.

In terms of what this could mean in the development of a cure, Dr Schindler said earlier detection of plaques could “speed up the process so we can find an effective drug faster. 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.

“Of course this has to be proven, but we think it might work. But to do this, you have to have a good test.”

One in six over-80s in the UK have dementia, with Alzheimer’s being the most common form. There are also 42,000 under-65s living with the disease. While these numbers are already substantial, they’re expected to increase in the coming years, making finding ways to effectively tackle it a pressing issue.