A blood test that can detect signs of Alzheimer's up to 20 years before the disease begins to have a debilitating effect was developed by researchers in the United States.
Scientists at the Washington University School of Medicine in St Louis in Missouri believe that the test can identify changes in the brain that suggest Alzheimer's with an accuracy of 94%, despite being much cheaper and simpler than a brain scan in PET.
The results of the study, published Thursday in the journal Neurology, represent a potential step forward in the fight against the disease.
"Right now we check people for clinical trials with brain scans, which take a lot of time and money, and enrollment requires years," said senior author Randall Bateman, one of the principal professors of neurology.
"But with a blood test, we could potentially examine thousands of people a month. This means we can enroll participants more efficiently in clinical trials, which will help us find treatments faster and could have a huge impact on the cost. of the illness and on the human suffering that derives from it. "
The researchers said they found a way to measure levels of beta-amyloid protein, a key indicator of Alzheimer's disease, in the blood. They can then use these levels to predict whether the protein has accumulated in the brain.
This analysis could therefore be combined with two other important risk factors of Alzheimer's disease – the age and the presence of the APOE4 genetic variant – to accurately identify relevant changes in the brain.
The researchers said that protein clots begin to form in the brain up to two decades before the start of the characteristic memory loss, suggesting that the tests could be used to predict Alzheimer's years in advance.
However, the benefits of such tests would not be visible to the fullest extent until treatments to stop the disease are developed.
In January 2018, a team of scientists revealed their work on a test that used mass spectrometry techniques to identify patients with a rogue peptide in their blood plasma, indicating an accumulation of beta-amyloid in the brain.
The last study examined 158 people over the age of 50. All but 10 of the participants in the new study were cognitively normal and each provided at least one blood sample and underwent a PET brain scan.
The researchers found that the blood tests gave the same results as the PET analysis of 88% of the time, which was not satisfactory. In order to improve accuracy, scientists have begun to incorporate other risk factors, increasing the accuracy to over 90%.