Blood test for early detection of Alzheimer’s disease

By Dr. Ananya Mandal, MDApr 2 2012

Soon researchers may be able to detect signs of Alzheimer's disease before symptoms appear by a simple blood test. Currently, biological tests to diagnose Alzheimer's use invasive and costly procedures including brain imaging and spinal punctures.

The latest research comes from researchers from the University of Newcastle in NSW who have developed a predictive blood test that is between 85 per cent and 90 per cent accurate. The research is published in the PLoS (Public Library of Science) ONE journal.

The researchers analyzed data from the international Alzheimer’s Disease Neuroimaging Initiative (ADNI) database, the most comprehensive collection of Alzheimer’s data in the world. They took blood samples from 566 people, some with Alzheimer's disease, some with mild cognitive impairment and other with normal cognition, from a large international database. The team spent a year studying the levels of nearly 200 proteins in blood from the participants with the disease. They found that measuring the proteins means they can predict with around 90 per cent accuracy those who have the disease in its early stages.

Senior researcher Pablo Moscato said the aim was to develop a blood test that was cheap, reliable, non-invasive and could detect the disease early. “The holy grail is to try and have a test that ... will not involve imaging, because when you see something with images it is perhaps too late,” Prof Moscato told AAP.

He said the test could be used to screen the wider population, or when people presented to medical appointments with mild cognitive impairment. Prof Moscato said the test could be useful to determine whether such an impairment was likely to progress to Alzheimer's disease. He said if biological markers for Alzheimer's were detected early it would allow people to make lifestyle changes, such as more exercise. He said, “One of the things that we also expect is that people who are at risk can change some of their lifestyle. So some people are saying that, for example, exercise may be one of the things. In the future it could be a particular drug is used and then you can follow the action of the drug so it's really giving hope that we can even improve more of these tests.”

Prof Moscato explained that all people with mild cognitive impairment did not necessarily develop Alzheimer's. Some maintained that level of functioning or progressed to another form of dementia. He said the test, which analyses proteins in the blood, increased in accuracy when used with a second test done one year later to examine the change in protein levels.

Alzheimer's Australia national research manager Dr Chris Hatherly said it could also help advance research on medical treatments to delay or reverse the disease. “This is an important new development in the global effort to find simple, reliable and cost-effective measures to identify people with the earliest stages of dementia,” Dr Hatherly told AAP.

The study was funded by the University of Newcastle and the Hunter Medical Research Institute. The researchers work in collaboration with HMRI’s Information Based Medicine Program.  HMRI is a partnership between the University of Newcastle, Hunter New England Local Health District and the community.