Transient plasma p‐tau217 elevations after electroconvulsive therapy: A two‐case report

INTRODUCTION Plasma phosphorylated tau (p‐tau217) is increasingly used in the evaluation of Alzheimer's disease (AD). However, factors influencing its interpretation in real‐world settings remain incompletely defined. METHODS We describe a patient with repeated measurements of p‐tau217 after an acute course of electroconvulsive therapy (ECT), complemented by a second patient with repeated measurements obtained during maintenance ECT. RESULTS In the primary case, p‐tau217 was markedly elevated 3 weeks after completion of an acute ECT course (5.360 pg/mL; normal < 0.185 pg/mL), followed by a decline toward normal levels within weeks and normalization at follow‐up. Cerebrospinal fluid biomarkers and neuropsychological assessment were normal. A second patient undergoing maintenance ECT demonstrated fluctuating levels of p‐tau217. DISCUSSION ECT may induce transient elevations of p‐tau217 that could be misinterpreted as suggestive of AD pathology. The temporal profile suggests a reversible process distinct from amyloid‐driven tau pathology. Deferring p‐tau217 testing after ECT may reduce false‐positive results.