Blood biomarkers for Alzheimer's disease in clinical practice and trials

Blood-based biomarkers hold great promise to revolutionize the diagnostic and prognostic work-up of Alzheimer's disease (AD) in clinical practice. This is very timely, considering the recent development of anti-amyloid-beta (A beta) immunotherapies. Several assays for measuring phosphorylated tau (p-tau) in plasma exhibit high diagnostic accuracy in distinguishing AD from all other neurodegenerative diseases in patients with cognitive impairment. Prognostic models based on plasma p-tau levels can also predict future development of AD dementia in patients with mild cognitive complaints. The use of such high-performing plasma p-tau assays in the clinical practice of specialist memory clinics would reduce the need for more costly investigations involving cerebrospinal fluid samples or positron emission tomography. Indeed, blood-based biomarkers already facilitate identification of individuals with pre-symptomatic AD in the context of clinical trials. Longitudinal measurements of such biomarkers will also improve the detection of relevant disease-modifying effects of new drugs or lifestyle interventions. This Review provides an update on the most promising blood-based biomarkers relevant to Alzheimer's disease and how they can be used to substantially improve the diagnostic and prognostic work-up in clinical practice and trials.

Automated summary

Blood-based biomarkers have the potential to greatly improve the diagnosis and prognosis of Alzheimer's disease (AD) in clinical practice. Assays for measuring phosphorylated tau (p-tau) in plasma have high diagnostic accuracy in distinguishing AD from other neurodegenerative diseases in patients with cognitive impairment. These biomarkers can also predict the future development of AD dementia in patients with mild cognitive complaints. The use of such blood-based biomarkers can reduce the need for more costly investigations and facilitate identification of individuals with pre-symptomatic AD in clinical trials.