Comparison of plasma p-tau217 and p-tau181 in predicting amyloid positivity and prognosis among Korean memory clinic patients

We investigated plasma phosphorylated tau217 (p-tau217) and p-tau181 efficacy in predicting positive amyloid positron emission tomography (PET) results and cognitive stage transitions. Plasma p-tau217 and p-tau181 were measured in participants who were cognitively unimpaired (CU, n = 121), had mild cognitive impairment (n = 102), or dementia (n = 75) from two independent cohorts (Cohort 1: KBASE-V and Cohort 2: Asan) who underwent amyloid PET. In Cohort 1, plasma p-tau217 (area under the curve [AUC] = 0.938, P < 0.001) outperformed p-tau181 (AUC = 0.857, P < 0.001) in predicting amyloid PET positivity (P_difference < 0.001). In Cohort 2, p-tau217 (AUC = 0.893, P < 0.001) and p-tau181 (AUC = 0.856, P < 0.001) showed comparably good discrimination for predicting amyloid PET positivity (P = 0.377). P-tau217 (AUC = 0.852, P < 0.001) and p-tau181 (AUC = 0.828, P < 0.001) demonstrated similarly good discriminations for predicting cognitive stage transition (P_difference = 0.093). Plasma p-tau217 and p-tau181 predicted amyloid PET positivity and cognitive stage transitions well. Plasma p-tau217 might perform better, especially in the early stages.