Bayoumy S, Verberk IMW, den Dulk B, et al. - Several novel high-sensitive Simoa assays can allow robust measurement of phosphorylated tau (P-tau) isoforms.

• In studies that employed different assays and technology, plasma P-tau levels were shown to have a highly promising diagnostic value for Alzheimer disease (AD).

• In this study, the analytical and clinical (40 AD dementia patients, age 66±8years, 50%F; 40 age- and gender-matched controls) performance of six P-tau Simoa assays, including three P-tau181 (phosphorylated tau at threonine 181) (Eli Lilly, ADx, Quanterix), one P-tau217 (phosphorylated tau at threonine 217) (Eli Lilly), and two P-tau231 (phosphorylated tau at threonine 231) (ADx, Gothenburg), were compared.

• Robust analytical performance of all assays was evident, and especially P-tau217 Eli Lilly; P-tau231 Gothenburg and all P-tau181 assays demonstrated robust clinical performance to distinguish AD from controls, with area under the curves (AUCs) 0.936–0.995 (P-tau231 ADx: AUC = 0.719).

• Findings acquired using all P-tau181 assays, P-tau217 Eli Lilly assay, and P-tau231 Gothenburg assay strongly correlated, while there were moderate correlations with P-tau231 ADx results.