The potential clinical value of plasma biomarkers in Alzheimer's disease.

INTRODUCTION: Many people with cognitive complaints or impairment never receive an accurate diagnosis of the underlying condition, potentially impacting their access to appropriate treatment. To address this unmet need, plasma biomarker tests are being developed for use in Alzheimer's disease (AD). Plasma biomarker tests span various stages of development, including in vitro diagnostic devices (or tests) (IVDs), laboratory-developed tests (LDTs) and research use only devices (or tests) (RUOs). Understanding the differences between each test type is important for appropriate implementation into the AD diagnostic pathway and care continuum. METHODS: Authors reviewed scientific literature (PubMed, meeting abstracts and presentations, company press releases and websites) on AD plasma biomarkers. RESULTS: This article defines IVDs, LDTs, and RUOs, discusses potential clinical applications and highlights the steps necessary for their clinical implementation. DISCUSSION: Plasma biomarkers could revolutionize many areas of the AD diagnostic pathway and care continuum, but further research is needed. HIGHLIGHTS: There is a need for a minimally invasive Alzheimer's disease (AD) diagnostic tool. AD plasma biomarker tests exist at various stages of commercial development. Understanding the development stage of a test is important for its appropriate use. Plasma biomarker tests could function as a triage tool to streamline AD diagnosis. Further steps remain before AD plasma biomarkers can be used routinely.