Blood-based Alzheimer's disease biomarkers in a behavioral neurology clinic: Real-world implementation, clinical utility, and diagnostic performance

Abstract

INTRODUCTION: Blood-based biomarkers (BBMs) for Alzheimer's disease (AD), including plasma phosphorylated tau (p-tau), are increasingly used in clinical practice, but “real-world” implementation patterns, context-of-use (COU), clinical utility, and diagnostic performance are incompletely understood. METHODS: A retrospective analysis of the first year of BBM use in a tertiary level cognitive neurology subspecialty clinic was conducted, including review of COU, impact on diagnostic certainty, prescription of AD-related medications, and additional AD-biomarker testing. RESULTS: P-tau181 was ordered frequently to detect AD in a diverse cohort, across a wide spectrum of COU, including typical, early-onset, and atypical AD presentations; mixed etiology; AD co-pathology; and borderline symptoms. P-tau181 impacted diagnostic confidence, AD-related medication prescription, and follow-on testing. Renal impairment was a common confounder. CONCLUSIONS: Implementation of BBMs was feasible and impactful in a memory clinic, especially in a diagnostically complex and diverse patient population, underscoring the need for additional data from real-world settings. Highlights: Blood-based biomarkers (BBMs) were quickly adopted and accelerated precision diagnosis in a large memory clinic. BBM use cases were diverse and included all stages/types of AD and non-AD syndromes. Plasma p-tau has the potential to impact diagnostic certainty and clinical decision making. Diagnostic performance of p-tau is reasonable, though renal function impacts overall accuracy.