The new test measures two proteins — pTau217 and β-amyloid 1-42 — in the blood and calculates their numerical ratio. The data correlates with the presence or absence of amyloid plaques in the patient’s brain, reducing the need for expensive and hard-to-find PET scans. Protein plaques can usually be detected using PET and invasive analysis of cerebrospinal fluid. Now, people at risk will have a much simpler method for early diagnosis. The study’s findings are published on the Alzheimer’s Association website.
According to clinical testing results, 92% of people with positive results had amyloid plaques on PET scans or cerebrospinal fluid tests. 97% of participants with negative blood results had no signs of neurodegeneration on gold standard tests.
"This means that the new blood test can reliably predict the presence or absence of Alzheimer's disease amyloid pathology at the time of testing in people with cognitive impairment," the authors concluded.
At this stage, the test will be used in people over 55 with early signs of cognitive changes. The test will become a first-line tool for identifying patients who will be assigned a full examination to diagnose early-stage Alzheimer's disease.
Earlier, other US scientists presented a home test for Alzheimer's disease that uses the sense of smell. It turned out that reduced olfactory function in older people is more likely to indicate the presence of neurodegeneration.
