Key points from article :
A new blood test, called p-tau217, can detect Alzheimer's disease up to 15 years before symptoms appear.
The test measures levels of a protein called p-tau217 in the blood, which rise as Alzheimer's disease progresses.
The test is as accurate as a painful lumbar puncture and better than other Alzheimer's tests currently being developed.
Experts say the test could lead to a national screening program for everyone over 50, allowing for earlier treatment and potentially slowing the progression of the disease.
The test is already commercially available, but more research is needed to see how effective it is across different populations.
One in three people born in the UK today will develop dementia in their lifetime, making early diagnosis and treatment of Alzheimer's disease crucial.
The study, published in the Jama Neurology journal, suggests early detection could enhance the effectiveness of current treatments and potentially lead to the development of improved therapies.
