Experts say blood biomarkers could democratize Alzheimer's diagnosis but note limits, cost, and coverage gaps

For clinicians and patients, the meeting's most practical takeaway was that newer blood-based tests can broaden access to Alzheimer's disease diagnostics but do not yet replace full diagnostic workups. For anyone who doesn't know me, my name is Wren Vandiverady, a cognitive behavioral neurologist and clinical trialist at the UCSF Memory and Aging Center, he said as he began a technical overview of biomarkers and their clinical roles. Vandiverady described cerebrospinal fluid (CSF) assays, amyloid and tau PET imaging, MRI and EEG markers and the rapid rise of blood biomarkers that detect amyloid and phosphorylated tau.

Vandiverady walked the council through advantages and tradeoffs. He said CSF tests detect multiple proteins (amyloid, tau, synuclein) and have decades of clinical experience but require lumbar puncture and more complex clinic infrastructure; PET scanning provides localization and quantitative burden but is expensive and not universally available. "Pet scans are expensive, requires an expert reader that's not available at every center," he said, noting illustrative costs on his slide of roughly $5,000 for an amyloid PET and higher costs when additional tracers are used. He told the council that blood tests are "democratizing" diagnosis because they are easy to collect and scale, but cautioned that proliferation of commercial tests has created variability in accuracy and that insurance coverage is inconsistent.

The presentation named two blood assays that have received regulatory clearance for particular clinical contexts and explained their intended use groups: an amyloid ratio test (Fuji/Rebio Lumipulse) intended for symptomatic adults and a Roche pTau assay (pTau217/pTau181 family) used as a triage or confirmatory tool. Vandiverady emphasized appropriate context of use: "They're meant to be used by clinicians as part of a comprehensive workup," he said, adding that kidney disease and other comorbidities can distort some blood results and produce false positives.

Panel discussion after the talk focused on practical implementation. Retired Maj. Gen. James Hartsell asked whether plasma pTau217 requires a separate blood draw; Vandiverady replied tests typically need very little volume and "it can be added on to existing test" and that dried blood spots and remote collection approaches are being explored. Multiple presenters urged caution about routine primary-care screening: until prevention trials show an available intervention for asymptomatic people, testing in the preclinical population should be considered carefully. The advisory council agreed to follow up on reimbursement, laboratory standards, and clinician training needs.