New research has uncovered a unique and promising way to diagnose Alzheimer’s disease (AD) earlier – by analyzing AD biomarkers in the blood – and potentially limit the impact of dementia.

AD is the most common form of dementia, accounting for about 60 to 70 percent of cases, or more than 33 million cases worldwide, according to the World Health Organization. Currently incurable, AD is usually diagnosed when a person has significant difficulties with memory and thinking that affect their daily life.

University of Melbourne researcher Dr Brandon Mahan is leading a group of analytical geochemists from the Faculty of Science who are working with neurobiologists from the Faculty of Medicine, Dentistry and Health Sciences (based at The Florey) to develop a blood test that could enable earlier diagnosis of Alzheimer’s disease, as described in a paper published in Metalomics.

For the first time in the world, scientists have applied inorganic analytical geochemistry techniques originally developed for cosmochemistry (e.g. to study the formation and evolution of the Earth, Moon, other planets and asteroid samples) and then adapted these extremely sensitive techniques to search for early biomarkers of Alzheimer’s disease in human blood serum.

Serum potassium isotope levels were compared in 20 samples – 10 healthy and 10 Alzheimer’s disease patients from the Australian Imaging, Biomarker, and Lifestyle Study and the Biobank.

Our minimally invasive test assesses relative levels of potassium isotopes in human blood serum and shows the potential to diagnose AD before symptoms of cognitive decline or other disease manifestations appear, so that actions can be taken to reduce the effects.”

Dr Brandon Mahan, Senior Lecturer, University of Melbourne

Dr. Mahan added: “Our assay is scalable and, unlike protein-based diagnostics that can degrade during storage, avoids sample stability issues because it assesses an inorganic biomarker.”

Currently, the clinical diagnosis of Alzheimer’s disease is made based on a medical interview, neurological examination, assessment of cognitive, functional and behavioral functions, brain imaging, and analysis of proteins in cerebrospinal fluid or blood samples.

“Earlier diagnosis would enable earlier lifestyle changes and treatments that can help slow disease progression and give affected families more time to take action to reduce the social, emotional and financial impact of dementia,” said Dr. Mahan. “It could also allow patients to qualify for a wider range of clinical trials that advance research and may provide further medical benefits.

“My research team – the Melbourne Analytical Geochemistry Group – is looking for partners and support to continue this important research and development.”

Co-author Professor Ashley Bush of The Florey sees promising results from the small pilot study.

“Our blood test successfully identified AD and has diagnostic power that rivals leading blood tests currently used in clinical diagnosis,” said Professor Bush. “Significant further work is required to determine the ultimate utility of this promising technique.”

As the world’s population ages, the prevalence of AD is increasing. The number of people with dementia is predicted to double every 20 years, and the global cost of dementia is expected to rise to US$2.8 trillion by 2030. In 2024, more than 421,000 Australians will be living with dementia. It is the second leading cause of death in Australia and the leading cause of death among Australian women.