Biomarker Core: Summary/Abstract The Biomarker Core supports the ADNI study in two main areas. The first is biofluid sample management: (a) maintains highly annotated biofluid aliquot samples that are collected, processed and stored in accord with ADNI sample preparation and storage protocols in dedicated freezers in the ADNI Biobank at UPenn and continuously monitored 24/7; (b)helps to organize and participate in ongoing studies devoted to standardization of pre-analytical sample collection protocols (especially plasma most recently) and methods for measurement of AD biofluid biomarkers; and (c) organizes and transfers ADNI biofluid samples to investigators whose biomarker study was approved by the Resource Allocation Review Committee (RARC) to measure new biomarkers in ADNI biofluid samples using advanced analytical platforms and thereby enrich the ADNI biofluid biomarker profiles The second major area of responsibility is to make a recommendation for the most rugged and effective methodology for use in the Biomarker Core to perform plasma biomarker testing. The recommendation will be done in consultation with the ADNI PI, and with input by academic and PPSB industrial biomarker scientists, assay vendors, and further informed by results from “head to head” comparison studies. Once the decision on platform is made it will be implemented in the Biomarker Core laboratory to perform plasma biomarker testing for Aβ and ptau and other candidate biomarkers in all of the non-clinical 4,000 individuals with blood draws organized by Quest Diagnostics and all the in-clinic ADNI participants and more than 11,720 “legacy” ADNI plasma samples from 2,582 individuals. All of these efforts will provide highly standardized data for use in the assessments of multimodal biomarker relationships for AD disease detection and prediction of disease progression, as planned and described in the Project. In summary, the Biomarker Core Aims are to: 1. Obtain biofluid samples from ADNI sites, process, store 24/7 and transfer the samples to investigators approved by RARC. 2. Collaborate on test methods standardization in test-performance-multicenter-studies. This includes interlaboratory studies of “head-to-head” assessments of analytical performance and prediction accuracy for Aβ PET measured amyloid plaque burden for candidate analytical platforms and reagents for plasma Aβ and ptau measurements. 3. Selection of analytical methods and platform(s) and implementation in the Biomarker Core. 4. Collaboration with the Project and Biostatistics Core on modeling and analyses.