Abstract
INTRODUCTION: Plasma biomarkers are minimally invasive tool for identifying Alzheimer's disease pathology. However, evaluation of their clinical utility remains limited. METHODS: This ongoing, open-label, randomized, two-arm, multicenter, U.S., prospective, observational study enrolled 609 patients presenting for initial evaluation of cognitive impairment. Patients were randomized into tau phosphorylated at position 217 (p-tau217) tested (n = 391) and untested (n = 218) arms. RESULTS: Change in working diagnosis was observed for 70.5% of patients with a t-tau217 result (positive or negative) inconsistent with baseline working diagnosis compared to 2.3% with a result consistent with baseline working diagnosis and 15.6% of untested patients. When the result was consistent with baseline working diagnosis, a significant 15.7% increase in diagnostic confidence was observed compared to 1.7% in untested patients and 5.0% when the result was inconsistent with baseline working diagnosis. DISCUSSION: P-tau217 testing changed health care providers' intended management and working diagnosis and increased confidence in the diagnosis. HIGHLIGHTS: Evaluation of the clinical utility of plasma tau phosphorylated at position 217 (p-tau217) for identifying Alzheimer's disease pathology has been limited.In this study, the impact of p-tau testing on health care providers' diagnostic thinking in patients under evaluation for cognitive impairment was assessed.When the result was inconsistent with the working diagnosis, a change in the working diagnosis was observed in 70.5% of tested patients.When the result was consistent, diagnostic confidence increased by 15.7%.P-tau217 testing demonstrated clinical utility by changing the working diagnosis, increasing diagnostic confidence, and altering intended patient management.