2.2. Development and validation of the UGOT p‐tau217 assay

A novel sheep monoclonal antibody, which selectively binds to tau phosphorylated specifically at threonine‐217, was generated, characterized, and used as the capture antibody. A mouse monoclonal antibody (tau12, GenScript Biotech) raised against the N‐terminal region of tau was used for detection. In vitro phosphorylated recombinant full‐length tau‐441 (#TO8‐50FN, SignalChem) was used as the assay calibrator. Blood samples and calibrators were diluted with the assay diluent (Tau 2.0; #101556, Quanterix). Assay validation focused on within‐ and between‐run stability, dilution linearity, spike recovery, and determination of the lowest limit of quantification. Analytical validation followed protocols that were described previously. ²⁹ , ³⁰ Assay development work was done at the University of Gothenburg, Sweden. The resulting assay is hereby referred to as UGOT p‐tau217, since it originates from the University of Gothenburg.