Clinical studies have demonstrated a strong association between Alzheimer’s disease (AD) and delirium. A change to the Tau protein, which can lead to the formation of tangles in brain, is one of the hallmarks of AD pathology, and Tau phosphorylation at threonine 217 (Tau-PT217) and threonine 181 (Tau-PT181) are new plasma biomarkers that can detect early-stage AD. A clinical study led by investigators at Massachusetts General Hospital (MGH) has shown that plasma Tau-PT217 and Tau-PT181 are associated with incidence and severity of postoperative delirium. The findings are published in Annals of Surgery.