A blood test that can detect Alzheimer’s disease up to three years before the onset of symptoms has been developed by scientists who believe that it could lead to the early diagnosis of progressive dementia in elderly people.
The test raises ethical concerns, however, as it is only 90 per cent accurate in its current form – meaning that up to one in ten people could be wrongly diagnosed with a disease for which there is no effective treatment.
Researchers nevertheless believe that a blood test for Alzheimer’s could help in the search for a therapy or cure by identifying those people in the population at highest risk and who could therefore benefit most from experimental treatments.
The blood test is based on analysing the fatty chemicals – known as lipids – circulating in the bloodstream, which begin to change as a result of a breakdown in the membranes of the brain cells associated with Alzheimer’s.
Scientists have known that Alzheimer’s disease begins long before the onset of the diagnostic symptoms, such as memory loss or confusion, and have tried for many years to find ways of detecting these changes with simple tests that could be used in the clinic.