New blood test for Alzheimer’s aids in early detection

A new blood test that will diagnose Alzheimer's disease may soon hit the market, thanks to an innovative study from the Research Institute of the McGill University Health Centre (MUHC).

The findings have characterised a unique biochemical diagnosis, which identifies patients with this devastating disorder. This research, published in the month's issue of the Journal of Alzheimer's Disease, has implications for millions of sufferers worldwide.

"Until now, there has been no definitive diagnostic tool for Alzheimer's, other than post-mortem analysis of brain tissue," says senior author Dr Vassilios Papadopoulos, director of the MUHC Research Institute. "Our clinical study shows that a non-invasive blood test, based on a biochemical process, may be successfully used to diagnose Alzheimer's at an early stage and differentiate it from other types of dementia."

The biochemistry behind the test
Papadopoulos and colleagues based the Alzheimer's blood test on the production of a brain hormone called dehydroepiandrosterone (DHEA). This hormone is present at high levels in the brain where it has a wide range of biological effects.

The researchers were able to promote the production of DHEA, using a chemical process called oxidation, in blood taken from non-Alzheimer's patients. However, oxidation of blood from Alzheimer's patients did not result in an increase of DHEA.

"There is a clear correlation between the lack of ability to produce DHEA through oxidation in the blood and the degree of cognitive impairment found in Alzheimer's disease," says Papadopoulos. "We demonstrated we could accurately and repetitively detect Alzheimer's disease, with small samples of blood.  This test also allowed for differential diagnosis of early stages of Alzheimer's disease, suggesting this can be used as a test to diagnose the disease in its infancy."