Blood phosphorylated Tau181 reliably differentiates amyloid-positive from amyloid-negative subjects in the Alzheimer's disease continuum: A systematic review and meta-analysis.

INTRODUCTION

Blood-based biomarkers seem promising for the diagnosis of Alzheimer's disease (AD).

METHODS

We performed a systematic review and meta-analysis on the potential of blood phosphorylated Tau181 (p-tau181) to differentiate amyloid-positive (A+) and amyloid-negative (A-) subjects. Two meta-analyses were conducted, showing the mean p-tau values in blood and cerebrospinal fluid (CSF) in the A+ and A- group, and the second comparing the mean p-tau concentrations in blood and CSF among A+ versus A- participants, by laboratory assessment method.

RESULTS

Eighteen studies (2764 A+ and 5646 A- subjects) were included. The single-group meta-analysis showed mean higher blood p-tau181 values in the A+ than in the A- group. In the head-to-head meta-analysis, blood p-tau reliably differentiated A+ patients from A- participants.

DISCUSSION: Regardless of the laboratory technique, blood p-tau181 reliably differentiates A+ and A- subjects. Therefore, it might have important applications for early diagnosis and inclusion in clinical trials for AD patients.

HIGHLIGHTS: The role of blood-based biomarkers in discriminating AD patients is still uncertain.Blood p-tau181 distinguishes among amyloid-positive and amyloid-negative subjects.Blood p-tau181 might allow early diagnosis and inclusion in clinical trials.