Validation cohort was small
Dr. Palmqvist and colleagues acknowledged that a lack of data about APOE was a limitation of their validation analysis. Other limitations that they acknowledged were the small population size, which precluded subpopulation analysis, and the lack of improvement in predictive ability when they replicated the model that included plasma tau.
“Overall, the accuracies of the amyloid-beta 42 and amyloid-beta 40 assays are not sufficient to be used on their own as a clinical test of amyloid-beta positivity,” said Dr. Palmqvist and colleagues. “Additional assay development is needed before this can be recommended, possibly together with other blood biomarkers and screening tools in diagnostic algorithms.”
Even though additional validation studies are necessary, the present findings indicate “the potential usefulness blood assays might have, especially considering the ongoing great need to recruit large cohorts for Alzheimer’s disease drug trials in preclinical and prodromal stages,” the authors concluded.
This investigation was funded by foundations including the European Research Council, the Swedish Research Council, and the Knut and Alice Wallenberg foundation. Several authors are employees of the Roche Group. One author served on a scientific advisory board for Roche Diagnostics, and another received institutional research support from that company.
SOURCE: Palmqvist S et al. JAMA Neurol. 2019 Jun 24. .