Dementia breakthrough: New blood test detects signs 15 years before onset of disease

A blood test that can predict dementia up to 15 years before symptoms start could change the lives of thousands, a study found. Scientists identified 11 protein biomarkers in the blood of individuals who were later diagnosed with Alzheimer’s and similar diseases, allowing them to foresee the conditions with more than 90 per cent accuracy. The development, aided by artificial intelligence and described as “a breakthrough”, means the test could replace the expensive, time-consuming and invasive procedures currently available to patients – more than a third of whom are never diagnosed. The proteins may also help guide the development of new drugs to slow or even reverse dementia. Professor Jianfeng Feng, from the University of Warwick, said the simple tests could be seamlessly integrated into the NHS and used by GPs to screen patients. He said, “This is highly important for screening middle-aged to older individuals within the community who are at high risk of dementia.” Professor Feng added that future drugs may be developed to interact with the proteins, possibly offering new treatments. New drugs such as lecanemab and donanemab, which have not yet been approved for use in the UK, can slow the progress of Alzheimer’s if detected early. Testing currently involves lumbar punctures and PET scans, which use a radioactive substance to look for changes in the brain tissue, but the NHS has a limited number of scanners. It is intended that the test could revolutionise diagnosis and lead to earlier preventative treatment. However, any test must go through regulatory approval before it can be used. Dr Sheona Scales, of Alzheimer’s Research UK, described the findings as “fantastic progress”. She said “Finding better, more accessible ways to diagnose dementia is crucial... Blood tests could unlock early diagnosis and are showing great promise, but so far none has been validated for use in the UK.” The study, published in the journal Nature Aging, looked at blood samples from 52,645 individuals taken between 2006 and 2010. The 1,417 who went on to develop dementia had biomarkers in their blood up to 15 years earlier. Researcher Wei Cheng, from Fudan University in China, said “It is obviously a breakthrough. The... biomarkers are easy to access and non-invasive.” Professor Sir Stephen Powis, the NHS national medical director, has said dementia diagnosis rates have started to recover after the pandemic. He added, “Diagnosing dementia early can make a big difference so please come forward to your GP as soon as possible if you have any concerns.”