Blood test could spot Alzheimer’s decades before symptoms start
A SIMPLE blood test could diagnose Alzheimer’s disease decades before symptoms begin, research suggests.
Scientists have identified a protein that accumulates in the blood up to 20 years before memory loss kicks in and before any changes are visible in the brain.
They found that a blood test measuring levels of the protein, called p-tau217, is 98 per cent accurate at identifying people with Alzheimer’s.
A blood test has always been the ‘holy grail’ for Alzheimer’s researchers as it would allow early detection.
This means patients could begin treatment or be enrolled on drug trials in the early stages of the disease, when drugs are likely to be more effective and before the brain has suffered significant damage.
The condition can currently only be diagnosed through invasive and painful spinal taps, or expensive brain scans.
These are tricky to perform on large populations and are only carried out after patients begin displaying symptoms.
Doctors hope that the test could be widely available on the NHS within five years.
The research, by an international team from Sweden and the US, was presented yesterday at the Alzheimer’s Association International Conference.
The new blood test looks at levels of protein p-tau217 which accumulates in ‘tangles’ and clumps inside the brain cells of people with Alzheimer’s. Some of this tau protein leaks out of the brain into the blood.
Scientists at Lund University, Sweden, found the amount of
‘Lead to mass screening’
p-tau217 is seven times higher in the blood of people with Alzheimer’s than those without the condition.
Levels of the protein increase in the blood up to 20 years before the onset of dementia symptoms – well before the disease is visible in brain scans.
More than 1,400 people were enrolled in the study, and the blood test was between 89 and 98 per cent accurate at identifying which patients had Alzheimer’s, depending on how far advanced their disease was.
Some 850,000 people in the UK have dementia, and around two thirds of these have Alzheimer’s disease.
Fiona Carragher, from the Alzheimer’s Society, said: ‘A cost effective, accurate and non-invasive diagnostic test is a vital step in developing new treatments.
‘Excitingly, this blood test for tau appears to not only show signs of being able to accurately distinguish between Alzheimer’s disease and other neurodegenerative conditions, but also may detect changes before symptoms even appear.’
Scientists believe the test could allow people to be massscreened for Alzheimer’s at their GP surgery, in a similar way to how routine screening occurs for conditions such as high cholesterol.
Professor David Curtis, from the UCL Genetics Institute, said: ‘From a clinical point of view, this kind of research is enormously important. Many researchers believe that effective treatment for Alzheimer’s disease will need to be started before symptoms develop.’