Reacción a "A new blood test could help with the early detection of Alzheimer's, according to a study"

The researchers have looked at what happens when testing 1350 people, with an average age of 61, with the new blood tests that pick up the underlying protein changes that occur in Alzheimer’s disease. A relatively small proportion of people without dementia (15% or less, depending on the particular test) tested positive on these blood tests and these individuals tended to do worse on some, but not all, tests of thinking. 

This study has used the new blood tests-that have started to enter clinical practice-in a relatively large number of people below the age where cognitive symptoms become most frequent. This adds to our knowledge about how many people will have abnormal Alzheimer’s blood results at this age, and provides further information about how common these changes are. Because it is at a single time point, it does not tell us how about how the proportions in this group will change over time. It also only tested people who had managed to continue to be part of a study for several decades, and we do not know how this will have affected the proportions.

It is essential that we continue doing research like this and into the processes that lead to altered brain function in Alzheimer’s and other dementias. It is also critical that we keep in mind that having an abnormal blood test is not in itself a clinical diagnosis and does not mean that someone will inevitably get dementia. At the moment we only really understand what these tests mean when there is evidence of cognitive impairment, so they can be helpful where there has been a clinical assessment but we do not yet fully understand their implications when they have been done without any such assessment or in people where there is no objective evidence of cognitive difficulties.