Improved discrimination of autopsy-confirmed Alzheimer's disease (AD) from non-AD dementias using CSF P-tau181P

To establish diagnostic accuracy (acc) and optimal cut-off levels of CSF tau phosphorylated at threonine 181 (P-tau181P) for discriminating Alzheimer's disease (AD) from non-AD dementias in autopsy-confirmed dementia patients, CSF levels of β-amyloid peptide (Aβ1–42), total tau protein (T-tau) and P-tau181P from patients with definite AD (n = 95) and non-AD dementias (n = 50) were determined with single-parameter ELISA kits. Optimal P-tau181P cut-off levels for differentiating AD from pooled non-AD dementias, dementia with Lewy bodies (DLB) and frontotemporal dementia (FTD) were 50.4 pg/mL (acc = 0.73), 52.8 pg/mL (acc = 0.73) and 35.3 pg/mL (acc = 0.90), respectively.The optimal CSF P-tau181P cut-off level for discriminating AD from non-AD dementias was 50.4 pg/mL. Optimal CSF P-tau181P cut-off levels differed between non-AD diagnostic dementia categories.