Blood test shows promise for early diagnosis of Alzheimer's

Melbourne researchers have discovered a promising avenue for diagnosing Alzheimer’s disease (AD) earlier — by analysing AD biomarkers in blood — so that the impacts of dementia can be reduced.

AD is the most common form of dementia, estimated to contribute to 60–70% of cases, according to the World Health Organization. AD is usually diagnosed when a person is having significant difficulties with memory and thinking that impact their daily life, following an examination of their medical history, neurological exams, cognitive, functional and behavioural assessments, brain imaging, and protein analysis of cerebrospinal fluid or blood samples.

Dr Brandon Mahan leads a group of analytical geochemists at The University of Melbourne, who are collaborating with neuroscientists at The Florey to develop a blood test for earlier diagnosis of AD. Their research has been published in the journal Metallomics.

The researchers applied inorganic analytical geochemistry techniques, originally developed for cosmochemistry — for example, to study the formation and evolution of the Earth, the Moon, other planets and asteroid samples — and adapted these highly sensitive techniques to search for early biomarkers of AD in human blood serum. They compared the levels of potassium isotopes in blood serum in 20 samples — 10 healthy and 10 AD patients from the Australian Imaging, Biomarker and Lifestyle study and biobank.

“Our minimally invasive test assesses the relative levels of potassium isotopes in human blood serum and shows potential to diagnose AD before cognitive decline or other disease symptoms become apparent, so action can be taken to reduce the impacts,” Mahan said.

“Our test is scalable and — unlike protein-based diagnostics that can break down during storage — it avoids sample stability issues because it assesses an inorganic biomarker.”

Professor Ashley Bush from The Florey, a co-author on the research, sees promise in the results from the team’s small pilot study.

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

According to Mahan, earlier Alzheimer’s diagnosis would provide patients with the opportunity to enact lifestyle changes and take medications that can help slow disease progression. It could also make patients eligible for a wider variety of clinical trials, which may provide further medical benefits.

“My research team — the Melbourne Analytical Geochemistry group — seeks partners and support to continue this important research and development,” Mahan said.

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