New dual blood test reduces false positives in Alzheimer's screening

Alzheimer's disease is characterised by the accumulation of two proteins in the brain: amyloid-beta and tau. Tau normally stabilises the structure of nerve cells, but in this disease the protein undergoes chemical changes and begins to form tangles in the neurons. This altered form is known as p-tau217 and can be measured in the blood.

However, the disease develops slowly over many years, and signs of Alzheimer's in the brain can be detected in the blood up to 20 years before symptoms become apparent. A challenge inherent in using the new blood tests is determining whether the measurable biological changes are in fact the cause of the person's symptoms or whether they are due to something else.

The new blood tests that have recently come into use are effective at detecting early signs of Alzheimer's – sometimes almost too early, as the disease has not yet fully developed and the symptoms may therefore be caused by another condition. More than 30 per cent of the elderly population show some signs of Alzheimer's disease. We have therefore investigated a marker that is linked to a later stage of the disease, which may be more clinically useful."

Mattsson-Carlgren is a researcher at Lund University and works as a specialist physician at the memory clinic at Skåne University Hospital, and he led the research.