41 - Empowering primary care in the new era of Alzheimer’s disease diagnostics (25 min)

For decades, assessing Alzheimer’s disease (AD) pathology required expensive PET scans or invasive lumbar punctures, creating significant diagnostic bottlenecks at the neurologist’s office. In this episode, Maeson Latsko, PhD and Dr. Matt Stroh, PhD explore how groundbreaking blood-based biomarkers are completely changing the landscape of brain health. The conversation highlights the recent FDA clearance of a p-tau181 triage test to help rule out AD, as well as the power of advanced multibiomarker models. By combining plasma Aβ42/40 ratio and p-tau217, clinicians can now accurately predict amyloid PET positivity. Adding APOE4 allele count significantly reduces indeterminate results. This episode breaks down how these accessible tools are empowering primary care providers (PCPs) to confidently triage mild cognitive impairment (MCI), explore secondary causes of impairment, and streamline patient care well before a specialty referral is made. This episode will Introduce the shifting clinical landscape of Alzheimer's care, including the role of recently FDA-cleared p-tau181 tests in helping PCPs rule out AD pathobiology (2:15) Differentiate between normal age-related cognitive decline, mild cognitive impairment (MCI), dementia, and Alzheimer’s disease (4:30) Translate the pathophysiology of AD (amyloid plaques and tau tangles) into the clinical utility of advanced blood-based models, demonstrating how combining Aβ42/40 and p-tau217 accurately predicts amyloid PET positivity, while adding APOE4 significantly reduces indeterminate results (6:45) Outline an actionable primary care workflow for patients presenting with cognitive complaints, balancing AD biomarker testing with the assessment of secondary, reversible causes (14:10) Ordering information Quest AD-Detect ABeta 42/40 and p-tau217 Evaluation, Plasma Quest AD-Detect® Beta Amyloid 42/40 Ratio, Plasma Quest AD-Detect® Phosphorylated tau217 (p-tau217), Plasma Quest AD-Detect® Phosphorylated tau181 (p-tau181), Plasma Quest AD-Detect® Apolipoprotein E (ApoE) Isoform, Plasma Dementia Panel, Secondary Causes Additional resources Clinical Education Center | Quest Diagnostics Role of blood testing for Alzheimer’s disease biomarkers within the primary care setting | Quest Diagnostics Alzheimer's Risk Assessment | Quest Diagnostics The Coming Alzheimer's Disease Healthcare Revolution Survey Report AD Detect Multimarker Panel for PCPs | Quest Diagnostics   References Weber DM, Stroh MA, Taylor SW, et al. Development and clinical validation of blood-based multibiomarker models for the evaluation of brain amyloid pathology. Preprint. medRxiv. 2025;2025.02.27.25322892. April 2025. doi:10.1101/2025.02.27.25322892 Hansson O, Edelmayer RM, Boxer AL, et al. The Alzheimer's Association appropriate use recommendations for blood biomarkers in Alzheimer's disease. Alzheimers Dement. 2022;18(12):2669-2686. doi:10.1002/alz.12756 Jack CR Jr, Bennett DA, Blennow K, et al. NIA-AA Research Framework: Toward a biological definition of Alzheimer's disease. Alzheimers Dement. 2018;14(4):535-562. doi:10.1016/j.jalz.2018.02.018 Data on file. Quest Diagnostics; 2026.