Usefulness of Plasma Amyloid as a Prescreener for the Earliest Alzheimer Pathological Changes Depends on the Study Population

Recently, Verberk et al showed that plasma Aβ42/Aβ40 ratio has potential to identify Alzheimer pathological changes in subjects with subjective memory decline. 1 Furthermore, the inclusion of age and APOEε4 carriership in their multivariate model improved the likelihood of identification.Based on these results, Verberk and colleagues postulated that plasma Aβ42/Aβ40 ratio could be a potential prescreener to identify the earliest Alzheimer disease (AD) pathological changes in individuals with subjective memory decline.We aimed to extend the findings of Verberk et al, using the same statistical methods, but in a different population, namely healthy elderly subjects without memory complaints (N = 189).Subjects in this study were male and female, aged 72 years (mean; range = 65-86), with a mean Mini-Mental State Examination score of 28.8 (range = 25-30), and 15-item Geriatric Depression Scale score of 0.7 (mean; range = 0-5).Subjects were excluded if they had a cognitive or psychiatric disorder, or a history of drug and/or alcohol abuse.If a subject used