‘Milestone’ Alzheimer’s diagnosis blood test gets green light

GPs could soon be able to offer patients a ‘simple blood test’ to detect Alzheimer’s disease biomarkers up to 20 years before clinical symptoms appear, in a major step towards early detection and intervention.
 
While the highly anticipated test is only approved for use in clinical trials, it is likely to generate interest from doctors and patients alike and GPs are being urged to seek out education and training to get across the new tests and their scope as more information becomes available.
 
In a big week of announcements on Alzheimer’s disease, the Federal Government confirmed Roche Diagnostics has been authorised by the Therapeutic Goods Administration to supply the phosphorylated tau 217 (pTau217) test.
 
It says the test has potential to ‘rule in or rule out’ Alzheimer’s pathology, with biomarkers utilised to identify the presence of proteins believed to contribute to the onset of the disease, delivering greater diagnostic specificity for people with cognitive symptoms.
 
Federal Health and Ageing Minister Mark Butler described the ‘simple blood test’ as the ‘holy grail’ in the push for early detection of Alzheimer’s disease.
 
‘This diagnostic tool holds out the prospect of a quicker answer to the question about “what’s happening with me”?’ he said.
 
The new test follows approval last year for a pTau181 test, which aims to ‘rule out’ Alzheimer’s pathology in people experiencing cognitive symptoms.
 
It comes as Minister Butler officially opened the Asia-Pacific Centre of Excellence for Alzheimer’s Disease Diagnosis in Sydney, which brings together Neuroscience Research Australia (NeuRA) and Roche Diagnostics Australia.
 
The centre will process the newly approved pTau217 test, the pTau181, and ApoE4 testing that identifies if an APOE4 protein is present – if positive, then further genetic based testing is required (this testing is currently only recommended for people with a diagnosis of Alzheimer’s disease).
 
Associate Professor Emma Devenney, a neurologist and researcher with NeuRA, said the tests would provide a more rapid diagnosis for patients.
 
‘The use of these blood-based biomarkers to detect the presence of the proteins we believe cause Alzheimer’s disease can deliver earlier and quicker diagnoses, and that certainty has many benefits for patients,’ she told newsGP.
 
‘Currently the only way to be sure of the presence of those proteins is a PET scan or testing of [cerebrospinal fluid] CSF spinal fluid via a lumbar puncture – both of these are expensive, hard to access outside big cities, and intrusive.
 
‘These blood tests have shown similar levels of accuracy to PET scans and CSF testing.’
 
Associate Professor Devenney adds that the tests will initially be used in trial environments.
 
‘Currently, the Asia-Pacific Centre of Excellence will process these tests for clinical trials and research studies,’ she said.
 
‘Within the next few months, the clinical assays will be available (provisionally expected in October 2026) to provide the tests for specialists in clinical practice.’
 
Minister Butler said the centre’s work would pave the way to the tests being offered on the Medicare Benefits Schedule (MBS).
 
‘This collaboration will allow Australian data to be developed around an application to Medicare, or the Medical Services Advisory Committee,’ he said.
 
‘It is necessary to put a test like this on the MBS, that is what we want to see.
 
‘We want to see more tests on the MBS, we want to see more treatments on the PBS that provide Australians living with dementia and their families with relief.’
 
Asked when patients will be able to get this test at their general practices, Minister Butler said it will depend on the speed at which the data can be developed.
 
‘Obviously, I’d like to see it sooner rather than later, but we’ve got to have Australian data to be able to show a case for the clinical effectiveness to the exact advisory committee that really oversees the Medicare schedule,’ he said.
 
Dr Stephanie Daly, Chair of RACGP Specific Interests Dementia Sub-Group, describes the development as a ‘major milestone’ to help detect Alzheimer’s disease, but emphasises caution for those who have limited understanding of the disease and dementia. 
 
‘The tests are more accessible and cheaper than the current methods for determining the presence of Alzheimer’s pathology, such as CSF and amyloid PET scans,’ she told newsGP.
 
‘Importantly, they only detect one pathology and there are many pathologies that can lead to neurodegenerative brain conditions.
 
‘The GP needs to understand what the test is looking at and be able to counsel the patient on that.
 
‘They also should do a clinical assessment, decide on what the symptoms are related to, exclude other causes of changes in cognition, such as mood, biochemical abnormalities before doing tests such as these. My advice would be that it is best done after some education to understand the test, or in conjunction with specialist support at this point in time.’
 
While the new blood test offers strong potential for early diagnosis, there is still a road ahead, with no Australian guidelines currently available at this early stage, added Dr Daly, who is involved in a working group aiming to create guidance on their use.
 
‘Whilst these tests represent a paradigm shift in how we diagnose Alzheimer’s disease, I would urge GPs to seek out education on this before they implement the test,’ she said.
 
‘These tests should not be done in people who are asymptomatic as we do not know what the accuracy of the test is in this population – we do not know how to inform patients what the risk is in this population.’
 
Associate Professor Devenney said if GPs see patients who are concerned about their cognitive ability, they can refer to a non-GP specialist who may decide to order these tests.
 
‘It’s important for patients to understand that this test will be done in conjunction with other measures such as cognitive testing,’ she said.
 
‘Over the next few months, as the Centre of Excellence at NeuRA gets up and running, we expect to be able to process those tests from clinical referrals, with the ultimate aim of helping to show they are worthy of a Medicare item number.’
 
Dr Daly anticipates the tests will become a useful strategy in early intervention, potentially steering patients towards newer treatments or trials.
 
However, Minister Butler concedes there are ‘challenges with listing treatments that are on the global market.’
 
GPs interested in learning more about the pathology of Alzheimer’s disease can take part in an upcoming dementia training session – more information is available on the RACGP website .
 
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Alzheimer’s disease blood-based biomarkers dementia diagnostic testing early disease detection