Spitting image: can saliva biomarkers reflect Alzheimer's disease?

An easily accessible and non-invasive biofluid test to characterize the pathological hallmarks of Alzheimer's disease (AD), amyloid–β and tau, has been long sought after. Such tests could assist in the differential diagnosis of cognitive decline and, in the long pre-symptomatic phase of AD, highlight those who might benefit the most from therapeutic intervention. Cerebrospinal fluid (CSF) for amyloid–β (Aβ42/40), total tau (t-tau) and phosphorylated tau (p-tau) have led the way in this regard, and are now incorporated into diagnostic criteria for AD.