The full details of the implementation of the INNO-BIA Alz Bio3 immunoassay reagents on the Luminex analytical platform are described elsewhere [29 (link), 42 ]. Monoclonal antibodies (mAbs) are used in this assay, and the production process for the immunoassay kits includes in current production processes assurance of lot-to-lot consistency. These tests are relative quantitative assays for CSF Aβ1–42, t-tau and p-tau181 since no international reference standards for the analytes prepared in CSF are available. Each participating center used the same INNO-BIA AlzBio3 immunoassay kit (assay lot # 157353 and calibrator lot # 157379), provided for the study by Innogenetics, Ghent, Belgium. The kit reagents include a mixture of three xMAP color-coded carboxylated microspheres, each containing a bead set coupled with well-characterized capture mAbs specific for Aβ1–42 (4D7A3; bead region 56), t-tau (AT120; bead region 2) or p-tau181 (AT270; bead region 69), and a vial with analyte-specific biotinylated detector mAbs (3D6 for Aβ1–42 and HT7 for t-tau or p-tau181). Ready-to-use vials containing pre-determined calibrator concentrations for the three analytes were provided. Calibration curves were produced for each biomarker using aqueous buffered solutions that contained the combination of three bio-markers at concentrations ranging from 56 to 1,948 pg/mL for recombinant t-tau, 27–1,574 pg/mL for synthetic Aβ1–42 and 8–230 pg/mL for a synthetic tau peptide phosphorylated at the threonine 181 position (the p-tau181 standard; numbering according to the longest tau isoforms [13 (link)]). In addition to the calibrators, the immunoassay kit includes two quality control samples, produced in aqueous diluent, with pre-defined acceptable concentration ranges for the three biomarkers.