Projected effect of a high performing blood test on wait times for determination of Alzheimer's disease pathology in the United States

BackgroundBlood tests for Alzheimer's disease (AD) are emerging as alternative to amyloid positron emission tomography (PET) scans and analysis of cerebrospinal fluid (CSF). However, their effect on clinical decision-making and subsequent wait times in the diagnostic process remain unclear.ObjectiveTo estimate wait times in the diagnostic process to determine potential eligibility for amyloid-targeting treatments.MethodsWe used a structured expert consultation process to elicit how a blood test to rule out or to confirm AD pathology would inform decisions in primary and secondary care and a Markov model to project how those decisions would affect wait times for specialist visits and amyloid PET scans.ResultsCompared with referral decisions based on the results of a brief cognitive assessment, the addition of an AD blood test is projected to reduce wait times for subsequent specialist appointments by 35%. A blood test for confirmation of AD pathology would also eliminate wait times for amyloid PET scans.ConclusionsHigh-performing AD blood tests have the potential to streamline the diagnostic journey and reduce wait times.