Clinical and analytical comparison of six Simoa assays for plasma P-tau isoforms P-tau181, P-tau217, and P-tau231
Sherif Bayoumy, Inge M.W. Verberk, Ben den Dulk, Zulaiga Hussainali, Marissa D. Zwan, Wiesje M. van der Flier, Nicholas J. Ashton, Henrik Zetterberg, Kaj Blennow, Jeroen Vanbrabant, Erik Stoops, Eugeen Vanmechelen, Jeffrey L. Dage, Charlotte E. Teunissen
Abstract
INTRODUCTION: Studies using different assays and technologies showed highly promising diagnostic value of plasma phosphorylated (P-)tau levels for Alzheimer's disease (AD). We aimed to compare six P-tau Simoa assays, including three P-tau181 (Eli Lilly, ADx, Quanterix), one P-tau217 (Eli Lilly), and two P-tau231 (ADx, Gothenburg). METHODS: We studied the analytical (sensitivity, precision, parallelism, dilution linearity, and recovery) and clinical (40 AD dementia patients, age 66±8years, 50%F; 40 age- and sex-matched controls) performance of the assays. RESULTS: All assays showed robust analytical performance, and particularly P-tau217 Eli Lilly; P-tau231 Gothenburg and all P-tau181 assays showed robust clinical performance to differentiate AD from controls, with AUCs 0.936-0.995 (P-tau231 ADx: AUC = 0.719). Results obtained with all P-tau181 assays, P-tau217 Eli Lilly assay, and P-tau231 Gothenburg assay strongly correlated (Spearman's rho > 0.86), while correlations with P-tau231 ADx results were moderate (rho < 0.65). DISCUSSION: P-tau isoforms can be measured robustly by several novel high-sensitive Simoa assays.