Australia Introduces First Blood Test for Early Alzheimer’s Diagnosis

Australia has recently made significant strides in Alzheimer’s diagnostics with the introduction of Roche’s Elecsys® pTau 181 plasma test. This test, which received approval from the Therapeutic Goods Administration (TGA) and was listed on the Australian Register of Therapeutic Goods (ARTG) in October, is designed to support early diagnosis of Alzheimer’s disease. It is particularly aimed at adults aged 55 to 80 who exhibit subjective cognitive decline or mild cognitive impairment (MCI). The test is intended to help rule out amyloid pathology, a key indicator of Alzheimer’s, thereby facilitating timely intervention with treatments like monoclonal antibodies lecanemab and donanemab.

Australia’s first Alzheimer’s blood test is here

The Elecsys pTau 181 test is classified as a "rule out" test, meaning that while a negative result can effectively indicate the absence of Alzheimer’s, a positive result does not confirm the disease. The test has a negative predictive value of 93.8%, but its positive predictive value is only 46.6%, varying significantly between healthcare settings. For instance, in secondary care, the positive predictive value is estimated at 54%, compared to 33% in primary care. Consequently, patients with positive results are advised to seek further evaluation through cerebrospinal fluid analysis or amyloid PET scans.

Australia’s first Alzheimer’s blood test is here

Currently, the test is available through the Florey Institute’s National Dementia Diagnostics Laboratory (NDDL) at a cost of approximately $200, with results expected within one to two weeks. Roche is also developing a second test, the Elecsys® pTau 217 plasma test, anticipated to be more accurate and available by the second half of 2026. This upcoming test aims to provide both ruling out and ruling in capabilities for Alzheimer’s diagnosis.

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Despite the promising nature of the new test, a survey conducted by Healthed revealed that many general practitioners (GPs) feel unprepared to utilize these tests effectively. Only 9% of GPs reported feeling "very confident" in ordering the tests or counseling patients about the results. Concerns have been raised regarding the lack of education and support for GPs, with 58% expressing that inadequate training is a significant barrier to implementation. Dr. Marita Long, a GP and advisor to Dementia Australia, emphasized the need for clearer information and education to ensure that GPs can confidently integrate these tests into their practice.

Australia’s first Alzheimer’s blood test is here

Experts caution that while the Elecsys pTau 181 test represents a significant advancement, it is not a comprehensive solution for diagnosing cognitive decline. Dr. Stephanie Daly noted that the test only addresses Alzheimer’s pathology and does not account for other potential causes of cognitive impairment, such as vascular dementia or depression. Additionally, Dr. Michael Woodward highlighted the importance of understanding the limitations of the test and the necessity for follow-up evaluations.

Australia’s first Alzheimer’s blood test is here

• “This will be another test in the toolkit to help understand the cause of cognitive decline,” — Laura Parnas, Director of Medical and Scientific Affairs at Roche Diagnostics

FDA Clears Blood Test to Help Doctors Rule Out Alzheimer’s

• “GPs must understand the indications, performance, limitations, potential confounders and implications of these tests, and ensure informed consent is obtained and documented before ordering them.” — Dr. Marita Long, GP and Honorary Medical Advisor to Dementia Australia

Australia’s first Alzheimer’s blood test is here

• “General practice is uniquely complex; we manage patients across all life stages, systems, and conditions. While I strongly support and advocate for the timely diagnosis of dementia and recognise the importance of subtyping to guide care, we need clearer information and education to use these tests confidently and appropriately.” — Dr. Marita Long

Australia’s first Alzheimer’s blood test is here

The introduction of the Elecsys pTau 181 plasma test marks a pivotal moment in the early diagnosis of Alzheimer’s disease in Australia. However, the successful integration of this test into clinical practice will depend on addressing the educational gaps among healthcare providers and ensuring that patients receive comprehensive care beyond the initial testing.

Australia’s first Alzheimer’s blood test is here