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

## TL;DR

This study examines how blood-based Alzheimer's biomarkers are used in a real-world clinic, showing they help improve diagnosis and decision-making, especially in complex cases.

## Contribution

The study provides real-world evidence of blood-based Alzheimer's biomarker implementation and clinical impact in a diverse patient population.

## Key findings

- Plasma p-tau181 was frequently used across various Alzheimer's and non-AD cases to improve diagnostic confidence.
- Renal impairment was identified as a common confounder affecting the accuracy of p-tau181 results.
- Blood-based biomarkers accelerated precision diagnosis and influenced medication prescriptions and follow-up testing.

## Abstract

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.

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.

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.

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.

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.

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.