Description of Medical ServiceThe application requests consideration of two alternative methods for detecting presence of beta-amyloid (Aß) pathology in patients: Aß positron emission tomography (PET) and cerebrospinal fluid (CSF) Alzheimer Disease (AD) protein biomarker testing. Aß PET offers direct confirmation of the presence of Aß brain pathology. PET is a minimally invasive diagnostic imaging technique used to distinguish normal from abnormal tissue in numerous indications including neurologic disorders. It is the only antemortem imaging technique that can directly confirm the presence of Aß brain pathology. Aß PET imaging employs a radioisotope labelled tracer that is intravenously administered and travels to the brain to selectively bind Aß aggregates. Aâ PET creates an image which can inform on the density and location of the amyloid plaques within the brain.CSF AD biomarker testing also assesses the presence of Aß and tau brain pathology. Testing for CSF AD biomarkers is an alternative to Aß PET to confirm Aß pathology in order to determine eligibility for access to PBS-subsidised aducanumab. CSF AD biomarker testing is performed by in vitro immunoassays. A CSF sample is obtained by lumbar puncture using a standardised collection procedure. Concentrations of specific biomarkers (amyloid ß-42 peptides, total tau and phosphorylated tau) in the sample are then quantified by in vitro immunoassay methods, and amyloid positivity or negativity determined.The co-dependent intervention, aducanumab, is a proposed disease modifying medicine for patients with a clinical diagnosis of early stage AD, who are confirmed positive for Aß brain pathology. The proposed assessments of Aß brain pathology are to identify suitable candidates for treatment with aducanumab.
Description of Medical ConditionAD is an insidiously progressive neurodegenerative disorder that represents the most common form of dementia. Mild cognitive impairment in the presence of Aß brain pathology as determined by either Aß PET or CSF AD biomarkers is the earliest symptomatic phase prior to the onset of dementia in the AD severity continuum. Accurate clinical diagnosis can be difficult in early stage AD. Aß plaque deposition in the brain, and/or lowered CSF levels of Aâ, are considered to be pathological hallmarks of AD and implicated in the pathophysiologic process underlying early AD progression. As such, in early stage AD, abnormal Aß levels can provide greater diagnostic certainty.
Reason for ApplicationNew MBS item
Medical Service TypeInvestigative
Previous Application Number/sNot Applicable
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